feat: add username/hostname support with IRC hostmask format (#82)

## Summary

Adds username and hostname support to sessions, enabling standard IRC hostmask format (`nick!user@host`) for WHOIS, WHO, and future `+b` ban matching.

closes #81

## Changes

### Schema (`001_initial.sql`)
- Added `username TEXT NOT NULL DEFAULT ''` and `hostname TEXT NOT NULL DEFAULT ''` columns to the `sessions` table

### Database layer (`internal/db/`)
- `CreateSession` now accepts `username` and `hostname` parameters; username defaults to nick if empty
- `RegisterUser` now accepts `username` and `hostname` parameters
- New `SessionHostInfo` type and `GetSessionHostInfo` query to retrieve username/hostname for a session
- `MemberInfo` now includes `Username` and `Hostname` fields
- `ChannelMembers` query updated to return username/hostname
- New `FormatHostmask(nick, username, hostname)` helper that produces `nick!user@host` format
- New `Hostmask()` method on `MemberInfo`

### Handler layer (`internal/handlers/`)
- Session creation (`POST /api/v1/session`) accepts optional `username` field; resolves hostname via reverse DNS of connecting client IP (respects `X-Forwarded-For` and `X-Real-IP` headers)
- Registration (`POST /api/v1/register`) accepts optional `username` field with the same hostname resolution
- Username validation regex: `^[a-zA-Z0-9_\-\[\]\\^{}|` + "\`" + `]{1,32}$`
- WHOIS (`311 RPL_WHOISUSER`) now returns the real username and hostname instead of nick/servername
- WHO (`352 RPL_WHOREPLY`) now returns the real username and hostname instead of nick/servername
- Extracted `validateHashcash` and `resolveUsername` helpers to keep functions under the linter's `funlen` limit
- Extracted `executeRegister` helper for the same reason
- Reverse DNS uses `(*net.Resolver).LookupAddr` with a 3-second timeout context

### Tests
- `TestCreateSessionWithUserHost` — verifies username/hostname are stored and retrievable
- `TestCreateSessionDefaultUsername` — verifies empty username defaults to nick
- `TestGetSessionHostInfoNotFound` — verifies error on nonexistent session
- `TestFormatHostmask` — verifies `nick!user@host` formatting
- `TestFormatHostmaskDefaults` — verifies fallback when username/hostname empty
- `TestMemberInfoHostmask` — verifies `Hostmask()` method on `MemberInfo`
- `TestChannelMembersIncludeUserHost` — verifies `ChannelMembers` returns username/hostname
- `TestRegisterUserWithUserHost` — verifies registration stores username/hostname
- `TestRegisterUserDefaultUsername` — verifies registration defaults username to nick
- `TestWhoisShowsHostInfo` — integration test verifying WHOIS returns the correct username
- `TestWhoShowsHostInfo` — integration test verifying WHO returns the correct username
- `TestSessionUsernameDefault` — integration test verifying default username in WHOIS
- All existing tests updated for new `CreateSession`/`RegisterUser` signatures

### README
- New "Hostmask" section documenting the `nick!user@host` format
- Updated session creation and registration API docs with the new `username` field
- Updated WHOIS/WHO numeric examples to show real username/hostname
- Updated sessions schema table with new columns

## Docker build

`docker build .` passes cleanly (lint, format, tests, build).

Co-authored-by: user <user@Mac.lan guest wan>
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: clawbot <clawbot@eeqj.de>
Reviewed-on: #82
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/config/config.go

@@ -46,6 +46,8 @@ type Config struct {
 	FederationKey      string
 	SessionIdleTimeout string
 	HashcashBits       int
+	OperName           string
+	OperPassword       string
 	params             *Params
 	log                *slog.Logger
 }
@@ -78,6 +80,8 @@ func New(
 	viper.SetDefault("FEDERATION_KEY", "")
 	viper.SetDefault("SESSION_IDLE_TIMEOUT", "720h")
 	viper.SetDefault("NEOIRC_HASHCASH_BITS", "20")
+	viper.SetDefault("NEOIRC_OPER_NAME", "")
+	viper.SetDefault("NEOIRC_OPER_PASSWORD", "")
 
 	err := viper.ReadInConfig()
 	if err != nil {
@@ -104,6 +108,8 @@ func New(
 		FederationKey:      viper.GetString("FEDERATION_KEY"),
 		SessionIdleTimeout: viper.GetString("SESSION_IDLE_TIMEOUT"),
 		HashcashBits:       viper.GetInt("NEOIRC_HASHCASH_BITS"),
+		OperName:           viper.GetString("NEOIRC_OPER_NAME"),
+		OperPassword:       viper.GetString("NEOIRC_OPER_PASSWORD"),
 		log:                log,
 		params:             &params,
 	}

internal/db/auth.go

@@ -10,7 +10,12 @@ import (
 	"golang.org/x/crypto/bcrypt"
 )
 
-const bcryptCost = bcrypt.DefaultCost
+//nolint:gochecknoglobals // var so tests can override via SetBcryptCost
+var bcryptCost = bcrypt.DefaultCost
+
+// SetBcryptCost overrides the bcrypt cost.
+// Use bcrypt.MinCost in tests to avoid slow hashing.
+func SetBcryptCost(cost int) { bcryptCost = cost }
 
 var errNoPassword = errors.New(
 	"account has no password set",
@@ -20,8 +25,12 @@ var errNoPassword = errors.New(
 // and returns session ID, client ID, and token.
 func (database *Database) RegisterUser(
 	ctx context.Context,
-	nick, password string,
+	nick, password, username, hostname, remoteIP string,
 ) (int64, int64, string, error) {
+	if username == "" {
+		username = nick
+	}
+
 	hash, err := bcrypt.GenerateFromPassword(
 		[]byte(password), bcryptCost,
 	)
@@ -50,10 +59,11 @@ func (database *Database) RegisterUser(
 
 	res, err := transaction.ExecContext(ctx,
 		`INSERT INTO sessions
-		 (uuid, nick, password_hash,
-		  created_at, last_seen)
-		 VALUES (?, ?, ?, ?, ?)`,
-		sessionUUID, nick, string(hash), now, now)
+		 (uuid, nick, username, hostname, ip,
+		  password_hash, created_at, last_seen)
+		 VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+		sessionUUID, nick, username, hostname,
+		remoteIP, string(hash), now, now)
 	if err != nil {
 		_ = transaction.Rollback()
 
@@ -68,10 +78,11 @@ func (database *Database) RegisterUser(
 
 	clientRes, err := transaction.ExecContext(ctx,
 		`INSERT INTO clients
-		 (uuid, session_id, token,
+		 (uuid, session_id, token, ip, hostname,
 		  created_at, last_seen)
-		 VALUES (?, ?, ?, ?, ?)`,
-		clientUUID, sessionID, tokenHash, now, now)
+		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
+		clientUUID, sessionID, tokenHash,
+		remoteIP, hostname, now, now)
 	if err != nil {
 		_ = transaction.Rollback()
 
@@ -96,7 +107,7 @@ func (database *Database) RegisterUser(
 // client token.
 func (database *Database) LoginUser(
 	ctx context.Context,
-	nick, password string,
+	nick, password, remoteIP, hostname string,
 ) (int64, int64, string, error) {
 	var (
 		sessionID    int64
@@ -143,10 +154,11 @@ func (database *Database) LoginUser(
 
 	res, err := database.conn.ExecContext(ctx,
 		`INSERT INTO clients
-		 (uuid, session_id, token,
+		 (uuid, session_id, token, ip, hostname,
 		  created_at, last_seen)
-		 VALUES (?, ?, ?, ?, ?)`,
-		clientUUID, sessionID, tokenHash, now, now)
+		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
+		clientUUID, sessionID, tokenHash,
+		remoteIP, hostname, now, now)
 	if err != nil {
 		return 0, 0, "", fmt.Errorf(
 			"create login client: %w", err,

internal/db/auth_test.go

@@ -13,7 +13,7 @@ func TestRegisterUser(t *testing.T) {
 	ctx := t.Context()
 
 	sessionID, clientID, token, err :=
-		database.RegisterUser(ctx, "reguser", "password123")
+		database.RegisterUser(ctx, "reguser", "password123", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -38,6 +38,69 @@ func TestRegisterUser(t *testing.T) {
 	}
 }
 
+func TestRegisterUserWithUserHost(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.RegisterUser(
+		ctx, "reguhost", "password123",
+		"myident", "example.org", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := database.GetSessionHostInfo(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if info.Username != "myident" {
+		t.Fatalf(
+			"expected myident, got %s", info.Username,
+		)
+	}
+
+	if info.Hostname != "example.org" {
+		t.Fatalf(
+			"expected example.org, got %s",
+			info.Hostname,
+		)
+	}
+}
+
+func TestRegisterUserDefaultUsername(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.RegisterUser(
+		ctx, "regdefault", "password123", "", "", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := database.GetSessionHostInfo(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if info.Username != "regdefault" {
+		t.Fatalf(
+			"expected regdefault, got %s",
+			info.Username,
+		)
+	}
+}
+
 func TestRegisterUserDuplicateNick(t *testing.T) {
 	t.Parallel()
 
@@ -45,7 +108,7 @@ func TestRegisterUserDuplicateNick(t *testing.T) {
 	ctx := t.Context()
 
 	regSID, regCID, regToken, err :=
-		database.RegisterUser(ctx, "dupnick", "password123")
+		database.RegisterUser(ctx, "dupnick", "password123", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -55,7 +118,7 @@ func TestRegisterUserDuplicateNick(t *testing.T) {
 	_ = regToken
 
 	dupSID, dupCID, dupToken, dupErr :=
-		database.RegisterUser(ctx, "dupnick", "other12345")
+		database.RegisterUser(ctx, "dupnick", "other12345", "", "", "")
 	if dupErr == nil {
 		t.Fatal("expected error for duplicate nick")
 	}
@@ -72,7 +135,7 @@ func TestLoginUser(t *testing.T) {
 	ctx := t.Context()
 
 	regSID, regCID, regToken, err :=
-		database.RegisterUser(ctx, "loginuser", "mypassword")
+		database.RegisterUser(ctx, "loginuser", "mypassword", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -82,7 +145,7 @@ func TestLoginUser(t *testing.T) {
 	_ = regToken
 
 	sessionID, clientID, token, err :=
-		database.LoginUser(ctx, "loginuser", "mypassword")
+		database.LoginUser(ctx, "loginuser", "mypassword", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -103,6 +166,83 @@ func TestLoginUser(t *testing.T) {
 	}
 }
 
+func TestLoginUserStoresClientIPHostname(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	regSID, regCID, regToken, err := database.RegisterUser(
+		ctx, "loginipuser", "password123",
+		"", "", "10.0.0.1",
+	)
+
+	_ = regSID
+	_ = regCID
+	_ = regToken
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, clientID, _, err := database.LoginUser(
+		ctx, "loginipuser", "password123",
+		"10.0.0.99", "newhost.example.com",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	clientInfo, err := database.GetClientHostInfo(
+		ctx, clientID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if clientInfo.IP != "10.0.0.99" {
+		t.Fatalf(
+			"expected client IP 10.0.0.99, got %s",
+			clientInfo.IP,
+		)
+	}
+
+	if clientInfo.Hostname != "newhost.example.com" {
+		t.Fatalf(
+			"expected hostname newhost.example.com, got %s",
+			clientInfo.Hostname,
+		)
+	}
+}
+
+func TestRegisterUserStoresSessionIP(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.RegisterUser(
+		ctx, "regipuser", "password123",
+		"ident", "host.local", "172.16.0.5",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := database.GetSessionHostInfo(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if info.IP != "172.16.0.5" {
+		t.Fatalf(
+			"expected session IP 172.16.0.5, got %s",
+			info.IP,
+		)
+	}
+}
+
 func TestLoginUserWrongPassword(t *testing.T) {
 	t.Parallel()
 
@@ -110,7 +250,7 @@ func TestLoginUserWrongPassword(t *testing.T) {
 	ctx := t.Context()
 
 	regSID, regCID, regToken, err :=
-		database.RegisterUser(ctx, "wrongpw", "correctpass")
+		database.RegisterUser(ctx, "wrongpw", "correctpass", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -120,7 +260,7 @@ func TestLoginUserWrongPassword(t *testing.T) {
 	_ = regToken
 
 	loginSID, loginCID, loginToken, loginErr :=
-		database.LoginUser(ctx, "wrongpw", "wrongpass12")
+		database.LoginUser(ctx, "wrongpw", "wrongpass12", "", "")
 	if loginErr == nil {
 		t.Fatal("expected error for wrong password")
 	}
@@ -138,7 +278,7 @@ func TestLoginUserNoPassword(t *testing.T) {
 
 	// Create anonymous session (no password).
 	anonSID, anonCID, anonToken, err :=
-		database.CreateSession(ctx, "anon")
+		database.CreateSession(ctx, "anon", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -148,7 +288,7 @@ func TestLoginUserNoPassword(t *testing.T) {
 	_ = anonToken
 
 	loginSID, loginCID, loginToken, loginErr :=
-		database.LoginUser(ctx, "anon", "anything1")
+		database.LoginUser(ctx, "anon", "anything1", "", "")
 	if loginErr == nil {
 		t.Fatal(
 			"expected error for login on passwordless account",
@@ -167,7 +307,7 @@ func TestLoginUserNonexistent(t *testing.T) {
 	ctx := t.Context()
 
 	loginSID, loginCID, loginToken, err :=
-		database.LoginUser(ctx, "ghost", "password123")
+		database.LoginUser(ctx, "ghost", "password123", "", "")
 	if err == nil {
 		t.Fatal("expected error for nonexistent user")
 	}

internal/db/main_test.go

@@ -0,0 +1,14 @@
+package db_test
+
+import (
+	"os"
+	"testing"
+
+	"git.eeqj.de/sneak/neoirc/internal/db"
+	"golang.org/x/crypto/bcrypt"
+)
+
+func TestMain(m *testing.M) {
+	db.SetBcryptCost(bcrypt.MinCost)
+	os.Exit(m.Run())
+}

internal/db/queries.go

@@ -74,14 +74,40 @@ type ChannelInfo struct {
 type MemberInfo struct {
 	ID       int64     `json:"id"`
 	Nick     string    `json:"nick"`
+	Username string    `json:"username"`
+	Hostname string    `json:"hostname"`
 	LastSeen time.Time `json:"lastSeen"`
 }
 
+// Hostmask returns the IRC hostmask in
+// nick!user@host format.
+func (m *MemberInfo) Hostmask() string {
+	return FormatHostmask(m.Nick, m.Username, m.Hostname)
+}
+
+// FormatHostmask formats a nick, username, and hostname
+// into a standard IRC hostmask string (nick!user@host).
+func FormatHostmask(nick, username, hostname string) string {
+	if username == "" {
+		username = nick
+	}
+
+	if hostname == "" {
+		hostname = "*"
+	}
+
+	return nick + "!" + username + "@" + hostname
+}
+
 // CreateSession registers a new session and its first client.
 func (database *Database) CreateSession(
 	ctx context.Context,
-	nick string,
+	nick, username, hostname, remoteIP string,
 ) (int64, int64, string, error) {
+	if username == "" {
+		username = nick
+	}
+
 	sessionUUID := uuid.New().String()
 	clientUUID := uuid.New().String()
 
@@ -101,9 +127,11 @@ func (database *Database) CreateSession(
 
 	res, err := transaction.ExecContext(ctx,
 		`INSERT INTO sessions
-		 (uuid, nick, created_at, last_seen)
-		 VALUES (?, ?, ?, ?)`,
-		sessionUUID, nick, now, now)
+		 (uuid, nick, username, hostname, ip,
+		  created_at, last_seen)
+		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
+		sessionUUID, nick, username, hostname,
+		remoteIP, now, now)
 	if err != nil {
 		_ = transaction.Rollback()
 
@@ -118,10 +146,11 @@ func (database *Database) CreateSession(
 
 	clientRes, err := transaction.ExecContext(ctx,
 		`INSERT INTO clients
-		 (uuid, session_id, token,
+		 (uuid, session_id, token, ip, hostname,
 		  created_at, last_seen)
-		 VALUES (?, ?, ?, ?, ?)`,
-		clientUUID, sessionID, tokenHash, now, now)
+		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
+		clientUUID, sessionID, tokenHash,
+		remoteIP, hostname, now, now)
 	if err != nil {
 		_ = transaction.Rollback()
 
@@ -209,6 +238,135 @@ func (database *Database) GetSessionByNick(
 	return sessionID, nil
 }
 
+// SessionHostInfo holds the username, hostname, and IP
+// for a session.
+type SessionHostInfo struct {
+	Username string
+	Hostname string
+	IP       string
+}
+
+// GetSessionHostInfo returns the username, hostname,
+// and IP for a session.
+func (database *Database) GetSessionHostInfo(
+	ctx context.Context,
+	sessionID int64,
+) (*SessionHostInfo, error) {
+	var info SessionHostInfo
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		`SELECT username, hostname, ip
+		 FROM sessions WHERE id = ?`,
+		sessionID,
+	).Scan(&info.Username, &info.Hostname, &info.IP)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get session host info: %w", err,
+		)
+	}
+
+	return &info, nil
+}
+
+// ClientHostInfo holds the IP and hostname for a client.
+type ClientHostInfo struct {
+	IP       string
+	Hostname string
+}
+
+// GetClientHostInfo returns the IP and hostname for a
+// client.
+func (database *Database) GetClientHostInfo(
+	ctx context.Context,
+	clientID int64,
+) (*ClientHostInfo, error) {
+	var info ClientHostInfo
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		`SELECT ip, hostname
+		 FROM clients WHERE id = ?`,
+		clientID,
+	).Scan(&info.IP, &info.Hostname)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get client host info: %w", err,
+		)
+	}
+
+	return &info, nil
+}
+
+// SetSessionOper sets the is_oper flag on a session.
+func (database *Database) SetSessionOper(
+	ctx context.Context,
+	sessionID int64,
+	isOper bool,
+) error {
+	val := 0
+	if isOper {
+		val = 1
+	}
+
+	_, err := database.conn.ExecContext(
+		ctx,
+		`UPDATE sessions SET is_oper = ? WHERE id = ?`,
+		val, sessionID,
+	)
+	if err != nil {
+		return fmt.Errorf("set session oper: %w", err)
+	}
+
+	return nil
+}
+
+// IsSessionOper returns whether the session has oper
+// status.
+func (database *Database) IsSessionOper(
+	ctx context.Context,
+	sessionID int64,
+) (bool, error) {
+	var isOper int
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		`SELECT is_oper FROM sessions WHERE id = ?`,
+		sessionID,
+	).Scan(&isOper)
+	if err != nil {
+		return false, fmt.Errorf(
+			"check session oper: %w", err,
+		)
+	}
+
+	return isOper != 0, nil
+}
+
+// GetLatestClientForSession returns the IP and hostname
+// of the most recently created client for a session.
+func (database *Database) GetLatestClientForSession(
+	ctx context.Context,
+	sessionID int64,
+) (*ClientHostInfo, error) {
+	var info ClientHostInfo
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		`SELECT ip, hostname FROM clients
+		 WHERE session_id = ?
+		 ORDER BY created_at DESC LIMIT 1`,
+		sessionID,
+	).Scan(&info.IP, &info.Hostname)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get latest client for session: %w", err,
+		)
+	}
+
+	return &info, nil
+}
+
 // GetChannelByName returns the channel ID for a name.
 func (database *Database) GetChannelByName(
 	ctx context.Context,
@@ -388,7 +546,8 @@ func (database *Database) ChannelMembers(
 	channelID int64,
 ) ([]MemberInfo, error) {
 	rows, err := database.conn.QueryContext(ctx,
-		`SELECT s.id, s.nick, s.last_seen
+		`SELECT s.id, s.nick, s.username,
+		   s.hostname, s.last_seen
 		 FROM sessions s
 		 INNER JOIN channel_members cm
 		   ON cm.session_id = s.id
@@ -408,7 +567,9 @@ func (database *Database) ChannelMembers(
 		var member MemberInfo
 
 		err = rows.Scan(
-			&member.ID, &member.Nick, &member.LastSeen,
+			&member.ID, &member.Nick,
+			&member.Username, &member.Hostname,
+			&member.LastSeen,
 		)
 		if err != nil {
 			return nil, fmt.Errorf(
@@ -859,6 +1020,26 @@ func (database *Database) GetUserCount(
 	return count, nil
 }
 
+// GetOperCount returns the number of sessions with oper
+// status.
+func (database *Database) GetOperCount(
+	ctx context.Context,
+) (int64, error) {
+	var count int64
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		"SELECT COUNT(*) FROM sessions WHERE is_oper = 1",
+	).Scan(&count)
+	if err != nil {
+		return 0, fmt.Errorf(
+			"get oper count: %w", err,
+		)
+	}
+
+	return count, nil
+}
+
 // ClientCountForSession returns the number of clients
 // belonging to a session.
 func (database *Database) ClientCountForSession(

internal/db/queries_test.go

@@ -34,7 +34,7 @@ func TestCreateSession(t *testing.T) {
 	ctx := t.Context()
 
 	sessionID, _, token, err := database.CreateSession(
-		ctx, "alice",
+		ctx, "alice", "", "", "",
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -45,7 +45,7 @@ func TestCreateSession(t *testing.T) {
 	}
 
 	_, _, dupToken, dupErr := database.CreateSession(
-		ctx, "alice",
+		ctx, "alice", "", "", "",
 	)
 	if dupErr == nil {
 		t.Fatal("expected error for duplicate nick")
@@ -54,13 +54,249 @@ func TestCreateSession(t *testing.T) {
 	_ = dupToken
 }
 
+// assertSessionHostInfo creates a session and verifies
+// the stored username and hostname match expectations.
+func assertSessionHostInfo(
+	t *testing.T,
+	database *db.Database,
+	nick, inputUser, inputHost,
+	expectUser, expectHost string,
+) {
+	t.Helper()
+
+	sessionID, _, _, err := database.CreateSession(
+		t.Context(), nick, inputUser, inputHost, "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := database.GetSessionHostInfo(
+		t.Context(), sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if info.Username != expectUser {
+		t.Fatalf(
+			"expected username %s, got %s",
+			expectUser, info.Username,
+		)
+	}
+
+	if info.Hostname != expectHost {
+		t.Fatalf(
+			"expected hostname %s, got %s",
+			expectHost, info.Hostname,
+		)
+	}
+}
+
+func TestCreateSessionWithUserHost(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+
+	assertSessionHostInfo(
+		t, database,
+		"hostuser", "myident", "example.com",
+		"myident", "example.com",
+	)
+}
+
+func TestCreateSessionDefaultUsername(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+
+	// Empty username defaults to nick.
+	assertSessionHostInfo(
+		t, database,
+		"defaultu", "", "host.local",
+		"defaultu", "host.local",
+	)
+}
+
+func TestCreateSessionStoresIP(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, clientID, _, err := database.CreateSession(
+		ctx, "ipuser", "ident", "host.example.com",
+		"192.168.1.42",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := database.GetSessionHostInfo(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if info.IP != "192.168.1.42" {
+		t.Fatalf(
+			"expected session IP 192.168.1.42, got %s",
+			info.IP,
+		)
+	}
+
+	clientInfo, err := database.GetClientHostInfo(
+		ctx, clientID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if clientInfo.IP != "192.168.1.42" {
+		t.Fatalf(
+			"expected client IP 192.168.1.42, got %s",
+			clientInfo.IP,
+		)
+	}
+
+	if clientInfo.Hostname != "host.example.com" {
+		t.Fatalf(
+			"expected client hostname host.example.com, got %s",
+			clientInfo.Hostname,
+		)
+	}
+}
+
+func TestGetClientHostInfoNotFound(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+
+	_, err := database.GetClientHostInfo(
+		t.Context(), 99999,
+	)
+	if err == nil {
+		t.Fatal("expected error for nonexistent client")
+	}
+}
+
+func TestGetSessionHostInfoNotFound(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+
+	_, err := database.GetSessionHostInfo(
+		t.Context(), 99999,
+	)
+	if err == nil {
+		t.Fatal("expected error for nonexistent session")
+	}
+}
+
+func TestFormatHostmask(t *testing.T) {
+	t.Parallel()
+
+	result := db.FormatHostmask(
+		"nick", "user", "host.com",
+	)
+	if result != "nick!user@host.com" {
+		t.Fatalf(
+			"expected nick!user@host.com, got %s",
+			result,
+		)
+	}
+}
+
+func TestFormatHostmaskDefaults(t *testing.T) {
+	t.Parallel()
+
+	result := db.FormatHostmask("nick", "", "")
+	if result != "nick!nick@*" {
+		t.Fatalf(
+			"expected nick!nick@*, got %s",
+			result,
+		)
+	}
+}
+
+func TestMemberInfoHostmask(t *testing.T) {
+	t.Parallel()
+
+	member := &db.MemberInfo{ //nolint:exhaustruct // test only uses hostmask fields
+		Nick:     "alice",
+		Username: "aliceident",
+		Hostname: "alice.example.com",
+	}
+
+	hostmask := member.Hostmask()
+	expected := "alice!aliceident@alice.example.com"
+
+	if hostmask != expected {
+		t.Fatalf(
+			"expected %s, got %s", expected, hostmask,
+		)
+	}
+}
+
+func TestChannelMembersIncludeUserHost(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sid, _, _, err := database.CreateSession(
+		ctx, "memuser", "myuser", "myhost.net", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	chID, err := database.GetOrCreateChannel(
+		ctx, "#hostchan",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = database.JoinChannel(ctx, chID, sid)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	members, err := database.ChannelMembers(ctx, chID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(members) != 1 {
+		t.Fatalf(
+			"expected 1 member, got %d", len(members),
+		)
+	}
+
+	if members[0].Username != "myuser" {
+		t.Fatalf(
+			"expected username myuser, got %s",
+			members[0].Username,
+		)
+	}
+
+	if members[0].Hostname != "myhost.net" {
+		t.Fatalf(
+			"expected hostname myhost.net, got %s",
+			members[0].Hostname,
+		)
+	}
+}
+
 func TestGetSessionByToken(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
 	ctx := t.Context()
 
-	_, _, token, err := database.CreateSession(ctx, "bob")
+	_, _, token, err := database.CreateSession(ctx, "bob", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -93,7 +329,7 @@ func TestGetSessionByNick(t *testing.T) {
 	ctx := t.Context()
 
 	charlieID, charlieClientID, charlieToken, err :=
-		database.CreateSession(ctx, "charlie")
+		database.CreateSession(ctx, "charlie", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -150,7 +386,7 @@ func TestJoinAndPart(t *testing.T) {
 	database := setupTestDB(t)
 	ctx := t.Context()
 
-	sid, _, _, err := database.CreateSession(ctx, "user1")
+	sid, _, _, err := database.CreateSession(ctx, "user1", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -199,7 +435,7 @@ func TestDeleteChannelIfEmpty(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	sid, _, _, err := database.CreateSession(ctx, "temp")
+	sid, _, _, err := database.CreateSession(ctx, "temp", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -234,7 +470,7 @@ func createSessionWithChannels(
 
 	ctx := t.Context()
 
-	sid, _, _, err := database.CreateSession(ctx, nick)
+	sid, _, _, err := database.CreateSession(ctx, nick, "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -317,7 +553,7 @@ func TestChangeNick(t *testing.T) {
 	ctx := t.Context()
 
 	sid, _, token, err := database.CreateSession(
-		ctx, "old",
+		ctx, "old", "", "", "",
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -401,7 +637,7 @@ func TestPollMessages(t *testing.T) {
 	ctx := t.Context()
 
 	sid, _, token, err := database.CreateSession(
-		ctx, "poller",
+		ctx, "poller", "", "", "",
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -508,7 +744,7 @@ func TestDeleteSession(t *testing.T) {
 	ctx := t.Context()
 
 	sid, _, _, err := database.CreateSession(
-		ctx, "deleteme",
+		ctx, "deleteme", "", "", "",
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -548,12 +784,12 @@ func TestChannelMembers(t *testing.T) {
 	database := setupTestDB(t)
 	ctx := t.Context()
 
-	sid1, _, _, err := database.CreateSession(ctx, "m1")
+	sid1, _, _, err := database.CreateSession(ctx, "m1", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	sid2, _, _, err := database.CreateSession(ctx, "m2")
+	sid2, _, _, err := database.CreateSession(ctx, "m2", "", "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -611,7 +847,7 @@ func TestEnqueueToClient(t *testing.T) {
 	ctx := t.Context()
 
 	_, _, token, err := database.CreateSession(
-		ctx, "enqclient",
+		ctx, "enqclient", "", "", "",
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -651,3 +887,133 @@ func TestEnqueueToClient(t *testing.T) {
 		t.Fatalf("expected 1, got %d", len(msgs))
 	}
 }
+
+func TestSetAndCheckSessionOper(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.CreateSession(
+		ctx, "opernick", "", "", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Initially not oper.
+	isOper, err := database.IsSessionOper(ctx, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if isOper {
+		t.Fatal("expected session not to be oper")
+	}
+
+	// Set oper.
+	err = database.SetSessionOper(ctx, sessionID, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	isOper, err = database.IsSessionOper(ctx, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !isOper {
+		t.Fatal("expected session to be oper")
+	}
+
+	// Unset oper.
+	err = database.SetSessionOper(ctx, sessionID, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	isOper, err = database.IsSessionOper(ctx, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if isOper {
+		t.Fatal("expected session not to be oper")
+	}
+}
+
+func TestGetLatestClientForSession(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.CreateSession(
+		ctx, "clientnick", "", "", "10.0.0.1",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	clientInfo, err := database.GetLatestClientForSession(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if clientInfo.IP != "10.0.0.1" {
+		t.Fatalf(
+			"expected IP 10.0.0.1, got %s",
+			clientInfo.IP,
+		)
+	}
+}
+
+func TestGetOperCount(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	// Create two sessions.
+	sid1, _, _, err := database.CreateSession(
+		ctx, "user1", "", "", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	sid2, _, _, err := database.CreateSession(
+		ctx, "user2", "", "", "",
+	)
+	_ = sid2
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Initially zero opers.
+	count, err := database.GetOperCount(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if count != 0 {
+		t.Fatalf("expected 0 opers, got %d", count)
+	}
+
+	// Set one as oper.
+	err = database.SetSessionOper(ctx, sid1, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	count, err = database.GetOperCount(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if count != 1 {
+		t.Fatalf("expected 1 oper, got %d", count)
+	}
+}

internal/db/schema/001_initial.sql

@@ -6,6 +6,10 @@ CREATE TABLE IF NOT EXISTS sessions (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     uuid TEXT NOT NULL UNIQUE,
     nick TEXT NOT NULL UNIQUE,
+    username TEXT NOT NULL DEFAULT '',
+    hostname TEXT NOT NULL DEFAULT '',
+    ip TEXT NOT NULL DEFAULT '',
+    is_oper INTEGER NOT NULL DEFAULT 0,
     password_hash TEXT NOT NULL DEFAULT '',
     signing_key TEXT NOT NULL DEFAULT '',
     away_message TEXT NOT NULL DEFAULT '',
@@ -20,6 +24,8 @@ CREATE TABLE IF NOT EXISTS clients (
     uuid TEXT NOT NULL UNIQUE,
     session_id INTEGER NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
     token TEXT NOT NULL UNIQUE,
+    ip TEXT NOT NULL DEFAULT '',
+    hostname TEXT NOT NULL DEFAULT '',
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
     last_seen DATETIME DEFAULT CURRENT_TIMESTAMP
 );

internal/handlers/api.go

@@ -2,9 +2,11 @@ package handlers
 
 import (
 	"context"
+	"crypto/subtle"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
 	"regexp"
 	"strconv"
@@ -30,6 +32,12 @@ var validChannelRe = regexp.MustCompile(
 	`^#[a-zA-Z0-9_\-]{1,63}$`,
 )
 
+var validUsernameRe = regexp.MustCompile(
+	`^[a-zA-Z0-9_\-\[\]\\^{}|` + "`" + `]{1,32}$`,
+)
+
+const dnsLookupTimeout = 3 * time.Second
+
 const (
 	maxLongPollTimeout = 30
 	pollMessageLimit   = 100
@@ -46,6 +54,55 @@ func (hdlr *Handlers) maxBodySize() int64 {
 	return defaultMaxBodySize
 }
 
+// clientIP extracts the connecting client's IP address
+// from the request, checking X-Forwarded-For and
+// X-Real-IP headers before falling back to RemoteAddr.
+func clientIP(request *http.Request) string {
+	if forwarded := request.Header.Get("X-Forwarded-For"); forwarded != "" {
+		// X-Forwarded-For can contain a comma-separated list;
+		// the first entry is the original client.
+		parts := strings.SplitN(forwarded, ",", 2) //nolint:mnd
+		ip := strings.TrimSpace(parts[0])
+
+		if ip != "" {
+			return ip
+		}
+	}
+
+	if realIP := request.Header.Get("X-Real-IP"); realIP != "" {
+		return strings.TrimSpace(realIP)
+	}
+
+	host, _, err := net.SplitHostPort(request.RemoteAddr)
+	if err != nil {
+		return request.RemoteAddr
+	}
+
+	return host
+}
+
+// resolveHostname performs a reverse DNS lookup on the
+// given IP address. Returns the first PTR record with the
+// trailing dot stripped, or the raw IP if lookup fails.
+func resolveHostname(
+	reqCtx context.Context,
+	addr string,
+) string {
+	resolver := &net.Resolver{} //nolint:exhaustruct // using default resolver
+
+	ctx, cancel := context.WithTimeout(
+		reqCtx, dnsLookupTimeout,
+	)
+	defer cancel()
+
+	names, err := resolver.LookupAddr(ctx, addr)
+	if err != nil || len(names) == 0 {
+		return addr
+	}
+
+	return strings.TrimSuffix(names[0], ".")
+}
+
 // authSession extracts the session from the client token.
 func (hdlr *Handlers) authSession(
 	request *http.Request,
@@ -155,6 +212,7 @@ func (hdlr *Handlers) handleCreateSession(
 ) {
 	type createRequest struct {
 		Nick     string `json:"nick"`
+		Username string `json:"username,omitempty"`
 		Hashcash string `json:"pow_token,omitempty"` //nolint:tagliatelle
 	}
 
@@ -171,30 +229,10 @@ func (hdlr *Handlers) handleCreateSession(
 		return
 	}
 
-	// Validate hashcash proof-of-work if configured.
-	if hdlr.params.Config.HashcashBits > 0 {
-		if payload.Hashcash == "" {
-			hdlr.respondError(
-				writer, request,
-				"hashcash proof-of-work required",
-				http.StatusPaymentRequired,
-			)
-
-			return
-		}
-
-		err = hdlr.hashcashVal.Validate(
-			payload.Hashcash, hdlr.params.Config.HashcashBits,
-		)
-		if err != nil {
-			hdlr.respondError(
-				writer, request,
-				"invalid hashcash stamp: "+err.Error(),
-				http.StatusPaymentRequired,
-			)
-
-			return
-		}
+	if !hdlr.validateHashcash(
+		writer, request, payload.Hashcash,
+	) {
+		return
 	}
 
 	payload.Nick = strings.TrimSpace(payload.Nick)
@@ -209,9 +247,40 @@ func (hdlr *Handlers) handleCreateSession(
 		return
 	}
 
+	username := resolveUsername(
+		payload.Username, payload.Nick,
+	)
+
+	if !validUsernameRe.MatchString(username) {
+		hdlr.respondError(
+			writer, request,
+			"invalid username format",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	hdlr.executeCreateSession(
+		writer, request, payload.Nick, username,
+	)
+}
+
+func (hdlr *Handlers) executeCreateSession(
+	writer http.ResponseWriter,
+	request *http.Request,
+	nick, username string,
+) {
+	remoteIP := clientIP(request)
+
+	hostname := resolveHostname(
+		request.Context(), remoteIP,
+	)
+
 	sessionID, clientID, token, err :=
 		hdlr.params.Database.CreateSession(
-			request.Context(), payload.Nick,
+			request.Context(),
+			nick, username, hostname, remoteIP,
 		)
 	if err != nil {
 		hdlr.handleCreateSessionError(
@@ -224,15 +293,64 @@ func (hdlr *Handlers) handleCreateSession(
 	hdlr.stats.IncrSessions()
 	hdlr.stats.IncrConnections()
 
-	hdlr.deliverMOTD(request, clientID, sessionID, payload.Nick)
+	hdlr.deliverMOTD(request, clientID, sessionID, nick)
 
 	hdlr.respondJSON(writer, request, map[string]any{
 		"id":    sessionID,
-		"nick":  payload.Nick,
+		"nick":  nick,
 		"token": token,
 	}, http.StatusCreated)
 }
 
+// validateHashcash validates a hashcash stamp if required.
+// Returns false if validation failed and a response was
+// already sent.
+func (hdlr *Handlers) validateHashcash(
+	writer http.ResponseWriter,
+	request *http.Request,
+	stamp string,
+) bool {
+	if hdlr.params.Config.HashcashBits == 0 {
+		return true
+	}
+
+	if stamp == "" {
+		hdlr.respondError(
+			writer, request,
+			"hashcash proof-of-work required",
+			http.StatusPaymentRequired,
+		)
+
+		return false
+	}
+
+	err := hdlr.hashcashVal.Validate(
+		stamp, hdlr.params.Config.HashcashBits,
+	)
+	if err != nil {
+		hdlr.respondError(
+			writer, request,
+			"invalid hashcash stamp: "+err.Error(),
+			http.StatusPaymentRequired,
+		)
+
+		return false
+	}
+
+	return true
+}
+
+// resolveUsername returns the trimmed username, defaulting
+// to the nick if empty.
+func resolveUsername(username, nick string) string {
+	username = strings.TrimSpace(username)
+	if username == "" {
+		return nick
+	}
+
+	return username
+}
+
 func (hdlr *Handlers) handleCreateSessionError(
 	writer http.ResponseWriter,
 	request *http.Request,
@@ -352,9 +470,19 @@ func (hdlr *Handlers) deliverLusers(
 	)
 
 	// 252 RPL_LUSEROP
+	operCount, operErr := hdlr.params.Database.
+		GetOperCount(ctx)
+	if operErr != nil {
+		hdlr.log.Error(
+			"lusers oper count", "error", operErr,
+		)
+
+		operCount = 0
+	}
+
 	hdlr.enqueueNumeric(
 		ctx, clientID, irc.RplLuserOp, nick,
-		[]string{"0"},
+		[]string{strconv.FormatInt(operCount, 10)},
 		"operator(s) online",
 	)
 
@@ -885,6 +1013,11 @@ func (hdlr *Handlers) dispatchCommand(
 		hdlr.handleQuit(
 			writer, request, sessionID, nick, body,
 		)
+	case irc.CmdOper:
+		hdlr.handleOper(
+			writer, request,
+			sessionID, clientID, nick, bodyLines,
+		)
 	case irc.CmdMotd, irc.CmdPing:
 		hdlr.dispatchInfoCommand(
 			writer, request,
@@ -1534,16 +1667,16 @@ func (hdlr *Handlers) deliverNamesNumerics(
 	)
 
 	if memErr == nil && len(members) > 0 {
-		nicks := make([]string, 0, len(members))
+		entries := make([]string, 0, len(members))
 
 		for _, mem := range members {
-			nicks = append(nicks, mem.Nick)
+			entries = append(entries, mem.Hostmask())
 		}
 
 		hdlr.enqueueNumeric(
 			ctx, clientID, irc.RplNamReply, nick,
 			[]string{"=", channel},
-			strings.Join(nicks, " "),
+			strings.Join(entries, " "),
 		)
 	}
 
@@ -2329,16 +2462,16 @@ func (hdlr *Handlers) handleNames(
 		ctx, chID,
 	)
 	if memErr == nil && len(members) > 0 {
-		nicks := make([]string, 0, len(members))
+		entries := make([]string, 0, len(members))
 
 		for _, mem := range members {
-			nicks = append(nicks, mem.Nick)
+			entries = append(entries, mem.Hostmask())
 		}
 
 		hdlr.enqueueNumeric(
 			ctx, clientID, irc.RplNamReply, nick,
 			[]string{"=", channel},
-			strings.Join(nicks, " "),
+			strings.Join(entries, " "),
 		)
 	}
 
@@ -2445,55 +2578,42 @@ func (hdlr *Handlers) executeWhois(
 	nick, queryNick string,
 ) {
 	ctx := request.Context()
-	srvName := hdlr.serverName()
 
 	targetSID, err := hdlr.params.Database.GetSessionByNick(
 		ctx, queryNick,
 	)
 	if err != nil {
-		hdlr.enqueueNumeric(
-			ctx, clientID, irc.ErrNoSuchNick, nick,
-			[]string{queryNick},
-			"No such nick/channel",
+		hdlr.whoisNotFound(
+			ctx, writer, request,
+			sessionID, clientID, nick, queryNick,
 		)
-		hdlr.enqueueNumeric(
-			ctx, clientID, irc.RplEndOfWhois, nick,
-			[]string{queryNick},
-			"End of /WHOIS list",
-		)
-		hdlr.broker.Notify(sessionID)
-		hdlr.respondJSON(writer, request,
-			map[string]string{"status": "ok"},
-			http.StatusOK)
 
 		return
 	}
 
-	// 311 RPL_WHOISUSER
-	hdlr.enqueueNumeric(
-		ctx, clientID, irc.RplWhoisUser, nick,
-		[]string{queryNick, queryNick, srvName, "*"},
-		queryNick,
+	hdlr.deliverWhoisUser(
+		ctx, clientID, nick, queryNick, targetSID,
 	)
 
-	// 312 RPL_WHOISSERVER
-	hdlr.enqueueNumeric(
-		ctx, clientID, irc.RplWhoisServer, nick,
-		[]string{queryNick, srvName},
-		"neoirc server",
+	// 313 RPL_WHOISOPERATOR — show if target is oper.
+	hdlr.deliverWhoisOperator(
+		ctx, clientID, nick, queryNick, targetSID,
 	)
 
-	// 317 RPL_WHOISIDLE
 	hdlr.deliverWhoisIdle(
 		ctx, clientID, nick, queryNick, targetSID,
 	)
 
-	// 319 RPL_WHOISCHANNELS
 	hdlr.deliverWhoisChannels(
 		ctx, clientID, nick, queryNick, targetSID,
 	)
 
-	// 318 RPL_ENDOFWHOIS
+	// 338 RPL_WHOISACTUALLY — oper-only.
+	hdlr.deliverWhoisActually(
+		ctx, clientID, nick, queryNick,
+		sessionID, targetSID,
+	)
+
 	hdlr.enqueueNumeric(
 		ctx, clientID, irc.RplEndOfWhois, nick,
 		[]string{queryNick},
@@ -2506,6 +2626,90 @@ func (hdlr *Handlers) executeWhois(
 		http.StatusOK)
 }
 
+// whoisNotFound sends the error+end numerics when the
+// target nick is not found.
+func (hdlr *Handlers) whoisNotFound(
+	ctx context.Context,
+	writer http.ResponseWriter,
+	request *http.Request,
+	sessionID, clientID int64,
+	nick, queryNick string,
+) {
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.ErrNoSuchNick, nick,
+		[]string{queryNick},
+		"No such nick/channel",
+	)
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplEndOfWhois, nick,
+		[]string{queryNick},
+		"End of /WHOIS list",
+	)
+	hdlr.broker.Notify(sessionID)
+	hdlr.respondJSON(writer, request,
+		map[string]string{"status": "ok"},
+		http.StatusOK)
+}
+
+// deliverWhoisUser sends RPL_WHOISUSER (311) and
+// RPL_WHOISSERVER (312).
+func (hdlr *Handlers) deliverWhoisUser(
+	ctx context.Context,
+	clientID int64,
+	nick, queryNick string,
+	targetSID int64,
+) {
+	srvName := hdlr.serverName()
+
+	username := queryNick
+	hostname := srvName
+
+	hostInfo, hostErr := hdlr.params.Database.
+		GetSessionHostInfo(ctx, targetSID)
+	if hostErr == nil && hostInfo != nil {
+		if hostInfo.Username != "" {
+			username = hostInfo.Username
+		}
+
+		if hostInfo.Hostname != "" {
+			hostname = hostInfo.Hostname
+		}
+	}
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisUser, nick,
+		[]string{queryNick, username, hostname, "*"},
+		queryNick,
+	)
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisServer, nick,
+		[]string{queryNick, srvName},
+		"neoirc server",
+	)
+}
+
+// deliverWhoisOperator sends RPL_WHOISOPERATOR (313) if
+// the target has server oper status.
+func (hdlr *Handlers) deliverWhoisOperator(
+	ctx context.Context,
+	clientID int64,
+	nick, queryNick string,
+	targetSID int64,
+) {
+	targetIsOper, err := hdlr.params.Database.
+		IsSessionOper(ctx, targetSID)
+	if err != nil || !targetIsOper {
+		return
+	}
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisOperator, nick,
+		[]string{queryNick},
+		"is an IRC operator",
+	)
+}
+
 func (hdlr *Handlers) deliverWhoisChannels(
 	ctx context.Context,
 	clientID int64,
@@ -2531,6 +2735,44 @@ func (hdlr *Handlers) deliverWhoisChannels(
 	)
 }
 
+// deliverWhoisActually sends RPL_WHOISACTUALLY (338)
+// with the target's current client IP and hostname, but
+// only when the querying session has server oper status
+// (o-line). Non-opers see nothing extra.
+func (hdlr *Handlers) deliverWhoisActually(
+	ctx context.Context,
+	clientID int64,
+	nick, queryNick string,
+	querierSID, targetSID int64,
+) {
+	isOper, err := hdlr.params.Database.IsSessionOper(
+		ctx, querierSID,
+	)
+	if err != nil || !isOper {
+		return
+	}
+
+	clientInfo, clErr := hdlr.params.Database.
+		GetLatestClientForSession(ctx, targetSID)
+	if clErr != nil {
+		return
+	}
+
+	actualHost := clientInfo.Hostname
+	if actualHost == "" {
+		actualHost = clientInfo.IP
+	}
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisActually, nick,
+		[]string{
+			queryNick,
+			clientInfo.IP,
+		},
+		"is actually using host "+actualHost,
+	)
+}
+
 // handleWho handles the WHO command.
 func (hdlr *Handlers) handleWho(
 	writer http.ResponseWriter,
@@ -2579,11 +2821,21 @@ func (hdlr *Handlers) handleWho(
 	)
 	if memErr == nil {
 		for _, mem := range members {
+			username := mem.Username
+			if username == "" {
+				username = mem.Nick
+			}
+
+			hostname := mem.Hostname
+			if hostname == "" {
+				hostname = srvName
+			}
+
 			// 352 RPL_WHOREPLY
 			hdlr.enqueueNumeric(
 				ctx, clientID, irc.RplWhoReply, nick,
 				[]string{
-					channel, mem.Nick, srvName,
+					channel, username, hostname,
 					srvName, mem.Nick, "H",
 				},
 				"0 "+mem.Nick,
@@ -2906,6 +3158,76 @@ func (hdlr *Handlers) HandleServerInfo() http.HandlerFunc {
 	}
 }
 
+// handleOper handles the OPER command for server operator authentication.
+func (hdlr *Handlers) handleOper(
+	writer http.ResponseWriter,
+	request *http.Request,
+	sessionID, clientID int64,
+	nick string,
+	bodyLines func() []string,
+) {
+	ctx := request.Context()
+
+	lines := bodyLines()
+	if len(lines) < 2 { //nolint:mnd // name + password
+		hdlr.respondIRCError(
+			writer, request, clientID, sessionID,
+			irc.ErrNeedMoreParams, nick,
+			[]string{irc.CmdOper},
+			"Not enough parameters",
+		)
+
+		return
+	}
+
+	operName := lines[0]
+	operPass := lines[1]
+
+	cfgName := hdlr.params.Config.OperName
+	cfgPass := hdlr.params.Config.OperPassword
+
+	if cfgName == "" || cfgPass == "" ||
+		subtle.ConstantTimeCompare([]byte(operName), []byte(cfgName)) != 1 ||
+		subtle.ConstantTimeCompare([]byte(operPass), []byte(cfgPass)) != 1 {
+		hdlr.enqueueNumeric(
+			ctx, clientID, irc.ErrNoOperHost, nick,
+			nil, "No O-lines for your host",
+		)
+		hdlr.broker.Notify(sessionID)
+		hdlr.respondJSON(writer, request,
+			map[string]string{"status": "error"},
+			http.StatusOK)
+
+		return
+	}
+
+	err := hdlr.params.Database.SetSessionOper(
+		ctx, sessionID, true,
+	)
+	if err != nil {
+		hdlr.log.Error(
+			"set oper failed", "error", err,
+		)
+		hdlr.respondError(
+			writer, request, "internal error",
+			http.StatusInternalServerError,
+		)
+
+		return
+	}
+
+	// 381 RPL_YOUREOPER
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplYoureOper, nick,
+		nil, "You are now an IRC operator",
+	)
+
+	hdlr.broker.Notify(sessionID)
+	hdlr.respondJSON(writer, request,
+		map[string]string{"status": "ok"},
+		http.StatusOK)
+}
+
 // handleAway handles the AWAY command. An empty body
 // clears the away status; a non-empty body sets it.
 func (hdlr *Handlers) handleAway(

internal/handlers/api_test.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -30,8 +31,14 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/stats"
 	"go.uber.org/fx"
 	"go.uber.org/fx/fxtest"
+	"golang.org/x/crypto/bcrypt"
 )
 
+func TestMain(m *testing.M) {
+	db.SetBcryptCost(bcrypt.MinCost)
+	os.Exit(m.Run())
+}
+
 const (
 	commandKey  = "command"
 	bodyKey     = "body"
@@ -102,7 +109,6 @@ func newTestServer(
 	)
 
 	app.RequireStart()
-	time.Sleep(100 * time.Millisecond)
 
 	httpSrv := httptest.NewServer(srv)
 
@@ -2131,6 +2137,249 @@ func TestSessionStillWorks(t *testing.T) {
 	}
 }
 
+// findNumericWithParams returns the first message matching
+// the given numeric code. Returns nil if not found.
+func findNumericWithParams(
+	msgs []map[string]any,
+	numeric string,
+) map[string]any {
+	want, _ := strconv.Atoi(numeric)
+
+	for _, msg := range msgs {
+		code, ok := msg["code"].(float64)
+		if ok && int(code) == want {
+			return msg
+		}
+	}
+
+	return nil
+}
+
+// getNumericParams extracts the params array from a
+// numeric message as a string slice.
+func getNumericParams(
+	msg map[string]any,
+) []string {
+	raw, exists := msg["params"]
+	if !exists || raw == nil {
+		return nil
+	}
+
+	arr, isArr := raw.([]any)
+	if !isArr {
+		return nil
+	}
+
+	result := make([]string, 0, len(arr))
+
+	for _, val := range arr {
+		str, isString := val.(string)
+		if isString {
+			result = append(result, str)
+		}
+	}
+
+	return result
+}
+
+func TestWhoisShowsHostInfo(t *testing.T) {
+	tserver := newTestServer(t)
+
+	token := tserver.createSessionWithUsername(
+		"whoisuser", "myident",
+	)
+
+	queryToken := tserver.createSession("querier")
+
+	_, lastID := tserver.pollMessages(queryToken, 0)
+
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: "WHOIS",
+		toKey:      "whoisuser",
+	})
+
+	msgs, _ := tserver.pollMessages(queryToken, lastID)
+
+	whoisMsg := findNumericWithParams(msgs, "311")
+	if whoisMsg == nil {
+		t.Fatalf(
+			"expected RPL_WHOISUSER (311), got %v",
+			msgs,
+		)
+	}
+
+	params := getNumericParams(whoisMsg)
+
+	if len(params) < 2 {
+		t.Fatalf(
+			"expected at least 2 params, got %v",
+			params,
+		)
+	}
+
+	if params[1] != "myident" {
+		t.Fatalf(
+			"expected username myident, got %s",
+			params[1],
+		)
+	}
+
+	_ = token
+}
+
+// createSessionWithUsername creates a session with a
+// specific username and returns the token.
+func (tserver *testServer) createSessionWithUsername(
+	nick, username string,
+) string {
+	tserver.t.Helper()
+
+	body, err := json.Marshal(map[string]string{
+		"nick":     nick,
+		"username": username,
+	})
+	if err != nil {
+		tserver.t.Fatalf("marshal session: %v", err)
+	}
+
+	resp, err := doRequest(
+		tserver.t,
+		http.MethodPost,
+		tserver.url(apiSession),
+		bytes.NewReader(body),
+	)
+	if err != nil {
+		tserver.t.Fatalf("create session: %v", err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusCreated {
+		respBody, _ := io.ReadAll(resp.Body)
+		tserver.t.Fatalf(
+			"create session: status %d: %s",
+			resp.StatusCode, respBody,
+		)
+	}
+
+	var result struct {
+		Token string `json:"token"`
+	}
+
+	_ = json.NewDecoder(resp.Body).Decode(&result)
+
+	return result.Token
+}
+
+func TestWhoShowsHostInfo(t *testing.T) {
+	tserver := newTestServer(t)
+
+	whoToken := tserver.createSessionWithUsername(
+		"whouser", "whoident",
+	)
+
+	tserver.sendCommand(whoToken, map[string]any{
+		commandKey: joinCmd, toKey: "#whotest",
+	})
+
+	queryToken := tserver.createSession("whoquerier")
+
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: joinCmd, toKey: "#whotest",
+	})
+
+	_, lastID := tserver.pollMessages(queryToken, 0)
+
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: "WHO",
+		toKey:      "#whotest",
+	})
+
+	msgs, _ := tserver.pollMessages(queryToken, lastID)
+
+	assertWhoReplyUsername(t, msgs, "whouser", "whoident")
+}
+
+func assertWhoReplyUsername(
+	t *testing.T,
+	msgs []map[string]any,
+	targetNick, expectedUsername string,
+) {
+	t.Helper()
+
+	for _, msg := range msgs {
+		code, isCode := msg["code"].(float64)
+		if !isCode || int(code) != 352 {
+			continue
+		}
+
+		params := getNumericParams(msg)
+		if len(params) < 5 || params[4] != targetNick {
+			continue
+		}
+
+		if params[1] != expectedUsername {
+			t.Fatalf(
+				"expected username %s in WHO, got %s",
+				expectedUsername, params[1],
+			)
+		}
+
+		return
+	}
+
+	t.Fatalf(
+		"expected RPL_WHOREPLY (352) for %s, msgs: %v",
+		targetNick, msgs,
+	)
+}
+
+func TestSessionUsernameDefault(t *testing.T) {
+	tserver := newTestServer(t)
+
+	// Create session without specifying username.
+	token := tserver.createSession("defaultusr")
+
+	queryToken := tserver.createSession("querier2")
+
+	_, lastID := tserver.pollMessages(queryToken, 0)
+
+	// WHOIS should show the nick as the username.
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: "WHOIS",
+		toKey:      "defaultusr",
+	})
+
+	msgs, _ := tserver.pollMessages(queryToken, lastID)
+
+	whoisMsg := findNumericWithParams(msgs, "311")
+	if whoisMsg == nil {
+		t.Fatalf(
+			"expected RPL_WHOISUSER (311), got %v",
+			msgs,
+		)
+	}
+
+	params := getNumericParams(whoisMsg)
+
+	if len(params) < 2 {
+		t.Fatalf(
+			"expected at least 2 params, got %v",
+			params,
+		)
+	}
+
+	// Username defaults to nick.
+	if params[1] != "defaultusr" {
+		t.Fatalf(
+			"expected default username defaultusr, got %s",
+			params[1],
+		)
+	}
+
+	_ = token
+}
+
 func TestNickBroadcastToChannels(t *testing.T) {
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("nick_a")
@@ -2552,3 +2801,444 @@ func TestChannelHashcashMissingBitsArg(t *testing.T) {
 		)
 	}
 }
+
+func TestNamesShowsHostmask(t *testing.T) {
+	tserver := newTestServer(t)
+
+	queryToken, lastID := setupChannelWithIdentMember(
+		tserver, "namesmember", "nmident",
+		"namesquery", "#namestest",
+	)
+
+	// Issue an explicit NAMES command.
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: "NAMES",
+		toKey:      "#namestest",
+	})
+
+	msgs, _ := tserver.pollMessages(queryToken, lastID)
+
+	assertNamesHostmask(
+		t, msgs, "namesmember", "nmident",
+	)
+}
+
+func TestNamesOnJoinShowsHostmask(t *testing.T) {
+	tserver := newTestServer(t)
+
+	// First user joins to populate the channel.
+	firstToken := tserver.createSessionWithUsername(
+		"joinmem", "jmident",
+	)
+
+	tserver.sendCommand(firstToken, map[string]any{
+		commandKey: joinCmd, toKey: "#joinnamestest",
+	})
+
+	// Second user joins; the JOIN triggers
+	// deliverNamesNumerics which should include
+	// hostmask data.
+	joinerToken := tserver.createSession("joiner")
+
+	tserver.sendCommand(joinerToken, map[string]any{
+		commandKey: joinCmd, toKey: "#joinnamestest",
+	})
+
+	msgs, _ := tserver.pollMessages(joinerToken, 0)
+
+	assertNamesHostmask(
+		t, msgs, "joinmem", "jmident",
+	)
+}
+
+// setupChannelWithIdentMember creates a member session
+// with username, joins a channel, then creates a querier
+// and joins the same channel. Returns the querier token
+// and last message ID.
+func setupChannelWithIdentMember(
+	tserver *testServer,
+	memberNick, memberUsername,
+	querierNick, channel string,
+) (string, int64) {
+	tserver.t.Helper()
+
+	memberToken := tserver.createSessionWithUsername(
+		memberNick, memberUsername,
+	)
+
+	tserver.sendCommand(memberToken, map[string]any{
+		commandKey: joinCmd, toKey: channel,
+	})
+
+	queryToken := tserver.createSession(querierNick)
+
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: joinCmd, toKey: channel,
+	})
+
+	_, lastID := tserver.pollMessages(queryToken, 0)
+
+	return queryToken, lastID
+}
+
+// assertNamesHostmask verifies that a RPL_NAMREPLY (353)
+// message contains the expected nick with hostmask format
+// (nick!user@host).
+func assertNamesHostmask(
+	t *testing.T,
+	msgs []map[string]any,
+	targetNick, expectedUsername string,
+) {
+	t.Helper()
+
+	for _, msg := range msgs {
+		code, ok := msg["code"].(float64)
+		if !ok || int(code) != 353 {
+			continue
+		}
+
+		raw, exists := msg["body"]
+		if !exists || raw == nil {
+			continue
+		}
+
+		arr, isArr := raw.([]any)
+		if !isArr || len(arr) == 0 {
+			continue
+		}
+
+		bodyStr, isStr := arr[0].(string)
+		if !isStr {
+			continue
+		}
+
+		// Look for the target nick's hostmask entry.
+		expected := targetNick + "!" +
+			expectedUsername + "@"
+
+		if !strings.Contains(bodyStr, expected) {
+			t.Fatalf(
+				"expected NAMES body to contain %q, "+
+					"got %q",
+				expected, bodyStr,
+			)
+		}
+
+		return
+	}
+
+	t.Fatalf(
+		"expected RPL_NAMREPLY (353) with hostmask "+
+			"for %s, msgs: %v",
+		targetNick, msgs,
+	)
+}
+
+const testOperName = "admin"
+const testOperPassword = "secretpass"
+
+// newTestServerWithOper creates a test server with oper
+// credentials configured (admin / secretpass).
+func newTestServerWithOper(
+	t *testing.T,
+) *testServer {
+	t.Helper()
+
+	dbPath := filepath.Join(
+		t.TempDir(), "test.db",
+	)
+
+	dbURL := "file:" + dbPath +
+		"?_journal_mode=WAL&_busy_timeout=5000"
+
+	var srv *server.Server
+
+	app := fxtest.New(t,
+		fx.Provide(
+			newTestGlobals,
+			logger.New,
+			func(
+				lifecycle fx.Lifecycle,
+				globs *globals.Globals,
+				log *logger.Logger,
+			) (*config.Config, error) {
+				cfg, err := config.New(
+					lifecycle, config.Params{ //nolint:exhaustruct
+						Globals: globs, Logger: log,
+					},
+				)
+				if err != nil {
+					return nil, fmt.Errorf(
+						"test config: %w", err,
+					)
+				}
+
+				cfg.DBURL = dbURL
+				cfg.Port = 0
+				cfg.HashcashBits = 0
+				cfg.OperName = testOperName
+				cfg.OperPassword = testOperPassword
+
+				return cfg, nil
+			},
+			newTestDB,
+			stats.New,
+			newTestHealthcheck,
+			newTestMiddleware,
+			newTestHandlers,
+			newTestServerFx,
+		),
+		fx.Populate(&srv),
+	)
+
+	app.RequireStart()
+
+	httpSrv := httptest.NewServer(srv)
+
+	t.Cleanup(func() {
+		httpSrv.Close()
+		app.RequireStop()
+	})
+
+	return &testServer{
+		httpServer: httpSrv,
+		t:          t,
+		fxApp:      app,
+	}
+}
+
+func TestOperCommandSuccess(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	token := tserver.createSession("operuser")
+	_, lastID := tserver.pollMessages(token, 0)
+
+	// Send OPER command.
+	tserver.sendCommand(token, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName, testOperPassword},
+	})
+
+	msgs, _ := tserver.pollMessages(token, lastID)
+
+	// Expect 381 RPL_YOUREOPER.
+	if !findNumeric(msgs, "381") {
+		t.Fatalf(
+			"expected RPL_YOUREOPER (381), got %v",
+			msgs,
+		)
+	}
+}
+
+func TestOperCommandFailure(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	token := tserver.createSession("badoper")
+	_, lastID := tserver.pollMessages(token, 0)
+
+	// Send OPER with wrong password.
+	tserver.sendCommand(token, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName, "wrongpass"},
+	})
+
+	msgs, _ := tserver.pollMessages(token, lastID)
+
+	// Expect 491 ERR_NOOPERHOST.
+	if !findNumeric(msgs, "491") {
+		t.Fatalf(
+			"expected ERR_NOOPERHOST (491), got %v",
+			msgs,
+		)
+	}
+}
+
+func TestOperCommandNeedMoreParams(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	token := tserver.createSession("shortoper")
+	_, lastID := tserver.pollMessages(token, 0)
+
+	// Send OPER with only one parameter.
+	tserver.sendCommand(token, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName},
+	})
+
+	msgs, _ := tserver.pollMessages(token, lastID)
+
+	// Expect 461 ERR_NEEDMOREPARAMS.
+	if !findNumeric(msgs, "461") {
+		t.Fatalf(
+			"expected ERR_NEEDMOREPARAMS (461), got %v",
+			msgs,
+		)
+	}
+}
+
+func TestOperWhoisShowsClientInfo(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	// Create a target user.
+	_ = tserver.createSession("target")
+
+	// Create an oper user.
+	operToken := tserver.createSession("theoper")
+	_, lastID := tserver.pollMessages(operToken, 0)
+
+	// Authenticate as oper.
+	tserver.sendCommand(operToken, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName, testOperPassword},
+	})
+
+	var msgs []map[string]any
+
+	msgs, lastID = tserver.pollMessages(operToken, lastID)
+
+	if !findNumeric(msgs, "381") {
+		t.Fatalf(
+			"expected RPL_YOUREOPER (381), got %v",
+			msgs,
+		)
+	}
+
+	// Now WHOIS the target.
+	tserver.sendCommand(operToken, map[string]any{
+		commandKey: "WHOIS",
+		toKey:      "target",
+	})
+
+	msgs, _ = tserver.pollMessages(operToken, lastID)
+
+	// Expect 338 RPL_WHOISACTUALLY with client IP.
+	whoisActually := findNumericWithParams(msgs, "338")
+	if whoisActually == nil {
+		t.Fatalf(
+			"expected RPL_WHOISACTUALLY (338) for "+
+				"oper WHOIS, got %v",
+			msgs,
+		)
+	}
+
+	params := getNumericParams(whoisActually)
+	if len(params) < 2 {
+		t.Fatalf(
+			"expected at least 2 params in 338, "+
+				"got %v",
+			params,
+		)
+	}
+
+	// First param should be the target nick.
+	if params[0] != "target" {
+		t.Fatalf(
+			"expected first param 'target', got %s",
+			params[0],
+		)
+	}
+
+	// Second param should be a non-empty IP.
+	if params[1] == "" {
+		t.Fatal("expected non-empty IP in 338 params")
+	}
+}
+
+func TestNonOperWhoisHidesClientInfo(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	// Create a target user.
+	_ = tserver.createSession("hidden")
+
+	// Create a regular (non-oper) user.
+	regToken := tserver.createSession("regular")
+	_, lastID := tserver.pollMessages(regToken, 0)
+
+	// WHOIS the target without oper status.
+	tserver.sendCommand(regToken, map[string]any{
+		commandKey: "WHOIS",
+		toKey:      "hidden",
+	})
+
+	msgs, _ := tserver.pollMessages(regToken, lastID)
+
+	// Should NOT see 338 RPL_WHOISACTUALLY.
+	if findNumeric(msgs, "338") {
+		t.Fatalf(
+			"non-oper should not see "+
+				"RPL_WHOISACTUALLY (338), got %v",
+			msgs,
+		)
+	}
+
+	// But should see 311 RPL_WHOISUSER (normal WHOIS).
+	if !findNumeric(msgs, "311") {
+		t.Fatalf(
+			"expected RPL_WHOISUSER (311), got %v",
+			msgs,
+		)
+	}
+}
+
+func TestWhoisShowsOperatorStatus(t *testing.T) {
+	tserver := newTestServerWithOper(t)
+
+	// Create oper user and authenticate.
+	operToken := tserver.createSession("iamoper")
+	_, lastID := tserver.pollMessages(operToken, 0)
+
+	tserver.sendCommand(operToken, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName, testOperPassword},
+	})
+
+	msgs, _ := tserver.pollMessages(operToken, lastID)
+
+	if !findNumeric(msgs, "381") {
+		t.Fatalf("expected 381, got %v", msgs)
+	}
+
+	// Another user does WHOIS on the oper.
+	queryToken := tserver.createSession("asker")
+	_, queryLastID := tserver.pollMessages(queryToken, 0)
+
+	tserver.sendCommand(queryToken, map[string]any{
+		commandKey: "WHOIS",
+		toKey:      "iamoper",
+	})
+
+	msgs, _ = tserver.pollMessages(queryToken, queryLastID)
+
+	// Should see 313 RPL_WHOISOPERATOR.
+	if !findNumeric(msgs, "313") {
+		t.Fatalf(
+			"expected RPL_WHOISOPERATOR (313) in "+
+				"WHOIS of oper, got %v",
+			msgs,
+		)
+	}
+}
+
+func TestOperNoOlineConfigured(t *testing.T) {
+	// Standard test server has no oper configured.
+	tserver := newTestServer(t)
+
+	token := tserver.createSession("nooline")
+	_, lastID := tserver.pollMessages(token, 0)
+
+	tserver.sendCommand(token, map[string]any{
+		commandKey: "OPER",
+		bodyKey:    []string{testOperName, "password"},
+	})
+
+	msgs, _ := tserver.pollMessages(token, lastID)
+
+	// Should get 491 since no o-line is configured.
+	if !findNumeric(msgs, "491") {
+		t.Fatalf(
+			"expected ERR_NOOPERHOST (491) when no "+
+				"o-line configured, got %v",
+			msgs,
+		)
+	}
+}

internal/handlers/auth.go

@@ -30,6 +30,7 @@ func (hdlr *Handlers) handleRegister(
 ) {
 	type registerRequest struct {
 		Nick     string `json:"nick"`
+		Username string `json:"username,omitempty"`
 		Password string `json:"password"`
 	}
 
@@ -58,6 +59,20 @@ func (hdlr *Handlers) handleRegister(
 		return
 	}
 
+	username := resolveUsername(
+		payload.Username, payload.Nick,
+	)
+
+	if !validUsernameRe.MatchString(username) {
+		hdlr.respondError(
+			writer, request,
+			"invalid username format",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
 	if len(payload.Password) < minPasswordLength {
 		hdlr.respondError(
 			writer, request,
@@ -68,11 +83,27 @@ func (hdlr *Handlers) handleRegister(
 		return
 	}
 
+	hdlr.executeRegister(
+		writer, request,
+		payload.Nick, payload.Password, username,
+	)
+}
+
+func (hdlr *Handlers) executeRegister(
+	writer http.ResponseWriter,
+	request *http.Request,
+	nick, password, username string,
+) {
+	remoteIP := clientIP(request)
+
+	hostname := resolveHostname(
+		request.Context(), remoteIP,
+	)
+
 	sessionID, clientID, token, err :=
 		hdlr.params.Database.RegisterUser(
 			request.Context(),
-			payload.Nick,
-			payload.Password,
+			nick, password, username, hostname, remoteIP,
 		)
 	if err != nil {
 		hdlr.handleRegisterError(
@@ -85,11 +116,11 @@ func (hdlr *Handlers) handleRegister(
 	hdlr.stats.IncrSessions()
 	hdlr.stats.IncrConnections()
 
-	hdlr.deliverMOTD(request, clientID, sessionID, payload.Nick)
+	hdlr.deliverMOTD(request, clientID, sessionID, nick)
 
 	hdlr.respondJSON(writer, request, map[string]any{
 		"id":    sessionID,
-		"nick":  payload.Nick,
+		"nick":  nick,
 		"token": token,
 	}, http.StatusCreated)
 }
@@ -167,11 +198,18 @@ func (hdlr *Handlers) handleLogin(
 		return
 	}
 
+	remoteIP := clientIP(request)
+
+	hostname := resolveHostname(
+		request.Context(), remoteIP,
+	)
+
 	sessionID, clientID, token, err :=
 		hdlr.params.Database.LoginUser(
 			request.Context(),
 			payload.Nick,
 			payload.Password,
+			remoteIP, hostname,
 		)
 	if err != nil {
 		hdlr.respondError(