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/* Copyright (C) 2019 C. McEnroe <june@causal.agency>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <err.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <tls.h>
#include "bounce.h"
enum Need {
NeedNick = 1 << 0,
NeedUser = 1 << 1,
NeedPass = 1 << 2,
NeedCapEnd = 1 << 3,
};
struct Client {
bool error;
struct tls *tls;
enum Need need;
bool serverTime;
char buf[4096];
size_t len;
};
struct Client *clientAlloc(struct tls *tls) {
struct Client *client = malloc(sizeof(*client));
if (!client) err(EX_OSERR, "malloc");
client->error = false;
client->tls = tls;
client->need = NeedNick | NeedUser | (clientPass ? NeedPass : 0);
client->serverTime = false;
client->len = 0;
return client;
}
void clientFree(struct Client *client) {
tls_close(client->tls);
tls_free(client->tls);
free(client);
}
bool clientError(const struct Client *client) {
return client->error;
}
void clientSend(struct Client *client, const char *ptr, size_t len) {
if (verbose) fprintf(stderr, "\x1B[34m%.*s\x1B[m", (int)len, ptr);
while (len) {
ssize_t ret = tls_write(client->tls, ptr, len);
// FIXME: Handle non-blocking?
if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) continue;
if (ret < 0) {
warnx("tls_write: %s", tls_error(client->tls));
client->error = true;
return;
}
ptr += ret;
len -= ret;
}
}
void clientFormat(struct Client *client, const char *format, ...) {
char buf[513];
va_list ap;
va_start(ap, format);
int len = vsnprintf(buf, sizeof(buf), format, ap);
va_end(ap);
assert(len > 0 && (size_t)len < sizeof(buf));
clientSend(client, buf, len);
}
static void passRequired(struct Client *client) {
clientFormat(
client,
":invalid 464 * :Password incorrect\r\n"
"ERROR :Password incorrect\r\n"
);
client->error = true;
}
typedef void Handler(struct Client *client, struct Message msg);
static void handleNick(struct Client *client, struct Message msg) {
(void)msg;
client->need &= ~NeedNick;
if (!client->need) stateSync(client);
if (client->need == NeedPass) passRequired(client);
}
static void handleUser(struct Client *client, struct Message msg) {
(void)msg;
// TODO: Identify client by username.
client->need &= ~NeedUser;
if (!client->need) stateSync(client);
if (client->need == NeedPass) passRequired(client);
}
static void handlePass(struct Client *client, struct Message msg) {
if (!msg.params[0] || strcmp(clientPass, msg.params[0])) {
passRequired(client);
} else {
client->need &= ~NeedPass;
if (!client->need) stateSync(client);
}
}
static void handleCap(struct Client *client, struct Message msg) {
if (!msg.params[0]) msg.params[0] = "";
if (!strcmp(msg.params[0], "END")) {
if (client->need & NeedCapEnd) {
client->need &= ~NeedCapEnd;
if (!client->need) stateSync(client);
}
} else if (!strcmp(msg.params[0], "LS")) {
client->need |= NeedCapEnd;
clientFormat(client, ":invalid CAP * LS :server-time\r\n");
} else if (!strcmp(msg.params[0], "REQ") && msg.params[1]) {
client->need |= NeedCapEnd;
if (!strcmp(msg.params[1], "server-time")) {
client->serverTime = true;
clientFormat(client, ":invalid CAP * ACK :server-time\r\n");
} else {
clientFormat(client, ":invalid CAP * NAK :%s\r\n", msg.params[1]);
}
} else if (!strcmp(msg.params[0], "LIST")) {
clientFormat(
client, ":invalid CAP * LIST :%s\r\n",
(client->serverTime ? "server-time" : "")
);
} else {
clientFormat(client, ":invalid 410 * :Invalid CAP subcommand\r\n");
}
}
static const struct {
const char *cmd;
Handler *fn;
} Handlers[] = {
{ "CAP", handleCap },
{ "NICK", handleNick },
{ "PASS", handlePass },
{ "USER", handleUser },
};
static void clientParse(struct Client *client, char *line) {
struct Message msg = parse(line);
if (!msg.cmd) {
// FIXME: Identify client in message.
warnx("no command");
client->error = true;
return;
}
for (size_t i = 0; i < ARRAY_LEN(Handlers); ++i) {
if (strcmp(msg.cmd, Handlers[i].cmd)) continue;
Handlers[i].fn(client, msg);
break;
}
}
static bool intercept(const char *line, size_t len) {
if (len >= 4 && !memcmp(line, "CAP ", 4)) return true;
// TODO: Intercept PRIVMSG to send to other clients.
return false;
}
void clientRecv(struct Client *client) {
ssize_t read = tls_read(
client->tls,
&client->buf[client->len], sizeof(client->buf) - client->len
);
if (read == TLS_WANT_POLLIN || read == TLS_WANT_POLLOUT) return;
if (read < 0) warnx("tls_read: %s", tls_error(client->tls));
if (read < 1) {
client->error = true;
return;
}
client->len += read;
char *crlf;
char *line = client->buf;
for (;;) {
crlf = memmem(line, &client->buf[client->len] - line, "\r\n", 2);
if (!crlf) break;
if (verbose) {
fprintf(stderr, "\x1B[33m%.*s\x1B[m\n", (int)(crlf - line), line);
}
if (client->need || intercept(line, crlf - line)) {
crlf[0] = '\0';
clientParse(client, line);
} else {
serverSend(line, crlf + 2 - line);
}
line = crlf + 2;
}
client->len -= line - client->buf;
memmove(client->buf, line, client->len);
}
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