source: lib/proxy.c

/*
 * gaim
 *
 * Copyright (C) 1998-1999, Mark Spencer <markster@marko.net>
 * Copyright (C) 2002-2004, Wilmer van der Gaast, Jelmer Vernooij
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#define BITLBEE_CORE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include "nogaim.h"
#include "proxy.h"
#include "base64.h"

char proxyhost[128] = "";
int proxyport = 0;
int proxytype = PROXY_NONE;
char proxyuser[128] = "";
char proxypass[128] = "";

/* Some systems don't know this one. It's not essential, so set it to 0 then. */
#ifndef AI_NUMERICSERV
#define AI_NUMERICSERV 0
#endif
#ifndef AI_ADDRCONFIG
#define AI_ADDRCONFIG 0
#endif

static GHashTable *phb_hash = NULL;

struct PHB {
        b_event_handler func, proxy_func;
        gpointer data, proxy_data;
        char *host;
        int port;
        int fd;
        gint inpa;
        struct addrinfo *gai, *gai_cur;
};

typedef int (*proxy_connect_func)(const char *host, unsigned short port_, struct PHB *phb);

static int proxy_connect_none(const char *host, unsigned short port_, struct PHB *phb);

static gboolean phb_free(struct PHB *phb, gboolean success)
{
        g_hash_table_remove(phb_hash, &phb->fd);

        if (!success) {
                if (phb->fd > 0) {
                        closesocket(phb->fd);
                }
                if (phb->func) {
                        phb->func(phb->data, -1, B_EV_IO_READ);
                }
        }
        if (phb->gai) {
                freeaddrinfo(phb->gai);
        }
        g_free(phb->host);
        g_free(phb);
        return FALSE;
}

/* calls phb->func safely by ensuring that the phb struct doesn't exist in the
 * case that proxy_disconnect() is called down there */
static gboolean phb_connected(struct PHB *phb, gint source)
{
        /* save func and data here */
        b_event_handler func = phb->func;
        gpointer data = phb->data;

        /* free the struct so that it can't be freed by the callback */
        phb_free(phb, TRUE);

        /* if any proxy_disconnect() call happens here, it will use the
         * fd (still open), look it up in the hash table, get NULL, and
         * proceed to close the fd and do nothing else */
        func(data, source, B_EV_IO_READ);

        return FALSE;
}

static gboolean proxy_connected(gpointer data, gint source, b_input_condition cond)
{
        struct PHB *phb = data;
        socklen_t len;
        int error = ETIMEDOUT;

        len = sizeof(error);

        if (getsockopt(source, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) {
                if ((phb->gai_cur = phb->gai_cur->ai_next)) {
                        int new_fd;
                        b_event_remove(phb->inpa);
                        if ((new_fd = proxy_connect_none(NULL, 0, phb))) {
                                b_event_remove(phb->inpa);
                                closesocket(source);
                                dup2(new_fd, source);
                                closesocket(new_fd);
                                phb->fd = source;
                                phb->inpa = b_input_add(source, B_EV_IO_WRITE, proxy_connected, phb);
                                return FALSE;
                        }
                }
                closesocket(source);
                source = -1;
                /* socket is dead, but continue to clean up */
        } else {
                sock_make_blocking(source);
        }

        freeaddrinfo(phb->gai);
        phb->gai = NULL;

        b_event_remove(phb->inpa);
        phb->inpa = 0;

        if (phb->proxy_func) {
                phb->proxy_func(phb->proxy_data, source, B_EV_IO_READ);
        } else {
                phb_connected(phb, source);
        }

        return FALSE;
}

static int proxy_connect_none(const char *host, unsigned short port_, struct PHB *phb)
{
        struct sockaddr_in me;
        int fd = -1;

        if (phb->gai_cur == NULL) {
                int ret;
                char port[6];
                struct addrinfo hints;

                g_snprintf(port, sizeof(port), "%d", port_);

                memset(&hints, 0, sizeof(struct addrinfo));
                hints.ai_family = AF_UNSPEC;
                hints.ai_socktype = SOCK_STREAM;
                hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;

                if (!(ret = getaddrinfo(host, port, &hints, &phb->gai))) {
                        phb->gai_cur = phb->gai;
                } else {
                        event_debug("gai(): %s\n", gai_strerror(ret));
                }
        }

        for (; phb->gai_cur; phb->gai_cur = phb->gai_cur->ai_next) {
                if ((fd = socket(phb->gai_cur->ai_family, phb->gai_cur->ai_socktype, phb->gai_cur->ai_protocol)) < 0) {
                        event_debug("socket failed: %d\n", errno);
                        continue;
                }

                sock_make_nonblocking(fd);

                if (global.conf->iface_out) {
                        me.sin_family = AF_INET;
                        me.sin_port = 0;
                        me.sin_addr.s_addr = inet_addr(global.conf->iface_out);

                        if (bind(fd, (struct sockaddr *) &me, sizeof(me)) != 0) {
                                event_debug("bind( %d, \"%s\" ) failure\n", fd, global.conf->iface_out);
                        }
                }

                event_debug("proxy_connect_none( \"%s\", %d ) = %d\n", host, port_, fd);

                if (connect(fd, phb->gai_cur->ai_addr, phb->gai_cur->ai_addrlen) < 0 && !sockerr_again()) {
                        event_debug("connect failed: %s\n", strerror(errno));
                        closesocket(fd);
                        fd = -1;
                        continue;
                } else {
                        phb->inpa = b_input_add(fd, B_EV_IO_WRITE, proxy_connected, phb);
                        phb->fd = fd;

                        break;
                }
        }

        if (fd < 0 && host) {
                phb_free(phb, TRUE);
        }

        return fd;
}


/* Connecting to HTTP proxies */

#define HTTP_GOODSTRING "HTTP/1.0 200"
#define HTTP_GOODSTRING2 "HTTP/1.1 200"

static gboolean http_canread(gpointer data, gint source, b_input_condition cond)
{
        int nlc = 0;
        int pos = 0;
        struct PHB *phb = data;
        char inputline[8192];

        b_event_remove(phb->inpa);

        while ((pos < sizeof(inputline) - 1) && (nlc != 2) && (read(source, &inputline[pos++], 1) == 1)) {
                if (inputline[pos - 1] == '\n') {
                        nlc++;
                } else if (inputline[pos - 1] != '\r') {
                        nlc = 0;
                }
        }
        inputline[pos] = '\0';

        if ((memcmp(HTTP_GOODSTRING, inputline, strlen(HTTP_GOODSTRING)) == 0) ||
            (memcmp(HTTP_GOODSTRING2, inputline, strlen(HTTP_GOODSTRING2)) == 0)) {
                return phb_connected(phb, source);
        }

        return phb_free(phb, FALSE);
}

static gboolean http_canwrite(gpointer data, gint source, b_input_condition cond)
{
        char cmd[384];
        struct PHB *phb = data;
        socklen_t len;
        int error = ETIMEDOUT;

        if (phb->inpa > 0) {
                b_event_remove(phb->inpa);
        }
        len = sizeof(error);
        if (getsockopt(source, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
                return phb_free(phb, FALSE);
        }
        sock_make_blocking(source);

        g_snprintf(cmd, sizeof(cmd), "CONNECT %s:%d HTTP/1.1\r\nHost: %s:%d\r\n", phb->host, phb->port,
                   phb->host, phb->port);
        if (send(source, cmd, strlen(cmd), 0) < 0) {
                return phb_free(phb, FALSE);
        }

        if (strlen(proxyuser) > 0) {
                char *t1, *t2;
                t1 = g_strdup_printf("%s:%s", proxyuser, proxypass);
                t2 = tobase64(t1);
                g_free(t1);
                g_snprintf(cmd, sizeof(cmd), "Proxy-Authorization: Basic %s\r\n", t2);
                g_free(t2);
                if (send(source, cmd, strlen(cmd), 0) < 0) {
                        return phb_free(phb, FALSE);
                }
        }

        g_snprintf(cmd, sizeof(cmd), "\r\n");
        if (send(source, cmd, strlen(cmd), 0) < 0) {
                return phb_free(phb, FALSE);
        }

        phb->inpa = b_input_add(source, B_EV_IO_READ, http_canread, phb);

        return FALSE;
}

static int proxy_connect_http(const char *host, unsigned short port, struct PHB *phb)
{
        phb->host = g_strdup(host);
        phb->port = port;
        phb->proxy_func = http_canwrite;
        phb->proxy_data = phb;

        return(proxy_connect_none(proxyhost, proxyport, phb));
}


/* Connecting to SOCKS4 proxies */

static gboolean s4_canread(gpointer data, gint source, b_input_condition cond)
{
        unsigned char packet[12];
        struct PHB *phb = data;

        b_event_remove(phb->inpa);

        memset(packet, 0, sizeof(packet));
        if (read(source, packet, 9) >= 4 && packet[1] == 90) {
                return phb_connected(phb, source);
        }

        return phb_free(phb, FALSE);
}

static gboolean s4_canwrite(gpointer data, gint source, b_input_condition cond)
{
        unsigned char packet[12];
        struct hostent *hp;
        struct PHB *phb = data;
        socklen_t len;
        int error = ETIMEDOUT;
        gboolean is_socks4a = (proxytype == PROXY_SOCKS4A);

        if (phb->inpa > 0) {
                b_event_remove(phb->inpa);
        }
        len = sizeof(error);
        if (getsockopt(source, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
                return phb_free(phb, FALSE);
        }
        sock_make_blocking(source);

        if (!is_socks4a && !(hp = gethostbyname(phb->host))) {
                return phb_free(phb, FALSE);
        }

        packet[0] = 4;
        packet[1] = 1;
        packet[2] = phb->port >> 8;
        packet[3] = phb->port & 0xff;
        if (is_socks4a) {
                packet[4] = 0;
                packet[5] = 0;
                packet[6] = 0;
                packet[7] = 1;
        } else {
                packet[4] = (unsigned char) (hp->h_addr_list[0])[0];
                packet[5] = (unsigned char) (hp->h_addr_list[0])[1];
                packet[6] = (unsigned char) (hp->h_addr_list[0])[2];
                packet[7] = (unsigned char) (hp->h_addr_list[0])[3];
        }
        packet[8] = 0;
        if (write(source, packet, 9) != 9) {
                return phb_free(phb, FALSE);
        }

        if (is_socks4a) {
                size_t host_len = strlen(phb->host) + 1; /* include the \0 */

                if (write(source, phb->host, host_len) != host_len) {
                        return phb_free(phb, FALSE);
                }
        }

        phb->inpa = b_input_add(source, B_EV_IO_READ, s4_canread, phb);

        return FALSE;
}

static int proxy_connect_socks4(const char *host, unsigned short port, struct PHB *phb)
{
        phb->host = g_strdup(host);
        phb->port = port;
        phb->proxy_func = s4_canwrite;
        phb->proxy_data = phb;

        return(proxy_connect_none(proxyhost, proxyport, phb));
}


/* Connecting to SOCKS5 proxies */

static gboolean s5_canread_again(gpointer data, gint source, b_input_condition cond)
{
        unsigned char buf[512];
        struct PHB *phb = data;

        b_event_remove(phb->inpa);

        if (read(source, buf, 10) < 10) {
                return phb_free(phb, FALSE);
        }
        if ((buf[0] != 0x05) || (buf[1] != 0x00)) {
                return phb_free(phb, FALSE);
        }

        return phb_connected(phb, source);
}

static void s5_sendconnect(gpointer data, gint source)
{
        unsigned char buf[512];
        struct PHB *phb = data;
        int hlen = strlen(phb->host);

        buf[0] = 0x05;
        buf[1] = 0x01;          /* CONNECT */
        buf[2] = 0x00;          /* reserved */
        buf[3] = 0x03;          /* address type -- host name */
        buf[4] = hlen;
        memcpy(buf + 5, phb->host, hlen);
        buf[5 + strlen(phb->host)] = phb->port >> 8;
        buf[5 + strlen(phb->host) + 1] = phb->port & 0xff;

        if (write(source, buf, (5 + strlen(phb->host) + 2)) < (5 + strlen(phb->host) + 2)) {
                phb_free(phb, FALSE);
                return;
        }

        phb->inpa = b_input_add(source, B_EV_IO_READ, s5_canread_again, phb);
}

static gboolean s5_readauth(gpointer data, gint source, b_input_condition cond)
{
        unsigned char buf[512];
        struct PHB *phb = data;

        b_event_remove(phb->inpa);

        if (read(source, buf, 2) < 2) {
                return phb_free(phb, FALSE);
        }

        if ((buf[0] != 0x01) || (buf[1] != 0x00)) {
                return phb_free(phb, FALSE);
        }

        s5_sendconnect(phb, source);

        return FALSE;
}

static gboolean s5_canread(gpointer data, gint source, b_input_condition cond)
{
        unsigned char buf[512];
        struct PHB *phb = data;

        b_event_remove(phb->inpa);

        if (read(source, buf, 2) < 2) {
                return phb_free(phb, FALSE);
        }

        if ((buf[0] != 0x05) || (buf[1] == 0xff)) {
                return phb_free(phb, FALSE);
        }

        if (buf[1] == 0x02) {
                unsigned int i = strlen(proxyuser), j = strlen(proxypass);
                buf[0] = 0x01;  /* version 1 */
                buf[1] = i;
                memcpy(buf + 2, proxyuser, i);
                buf[2 + i] = j;
                memcpy(buf + 2 + i + 1, proxypass, j);
                if (write(source, buf, 3 + i + j) < 3 + i + j) {
                        return phb_free(phb, FALSE);
                }

                phb->inpa = b_input_add(source, B_EV_IO_READ, s5_readauth, phb);
        } else {
                s5_sendconnect(phb, source);
        }

        return FALSE;
}

static gboolean s5_canwrite(gpointer data, gint source, b_input_condition cond)
{
        unsigned char buf[512];
        int i;
        struct PHB *phb = data;
        socklen_t len;
        int error = ETIMEDOUT;

        if (phb->inpa > 0) {
                b_event_remove(phb->inpa);
        }
        len = sizeof(error);
        if (getsockopt(source, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
                return phb_free(phb, FALSE);
        }
        sock_make_blocking(source);

        i = 0;
        buf[0] = 0x05;          /* SOCKS version 5 */
        if (proxyuser[0]) {
                buf[1] = 0x02;  /* two methods */
                buf[2] = 0x00;  /* no authentication */
                buf[3] = 0x02;  /* username/password authentication */
                i = 4;
        } else {
                buf[1] = 0x01;
                buf[2] = 0x00;
                i = 3;
        }

        if (write(source, buf, i) < i) {
                return phb_free(phb, FALSE);
        }

        phb->inpa = b_input_add(source, B_EV_IO_READ, s5_canread, phb);

        return FALSE;
}

static int proxy_connect_socks5(const char *host, unsigned short port, struct PHB *phb)
{
        phb->host = g_strdup(host);
        phb->port = port;
        phb->proxy_func = s5_canwrite;
        phb->proxy_data = phb;

        return(proxy_connect_none(proxyhost, proxyport, phb));
}

static const proxy_connect_func proxy_connect_funcs_array[] = {
        proxy_connect_none,   /* PROXY_NONE */
        proxy_connect_http,   /* PROXY_HTTP */
        proxy_connect_socks4, /* PROXY_SOCKS4 */
        proxy_connect_socks5, /* PROXY_SOCKS5 */
        proxy_connect_socks4, /* PROXY_SOCKS4A */
};

/* Export functions */

int proxy_connect(const char *host, int port, b_event_handler func, gpointer data)
{
        struct PHB *phb;
        proxy_connect_func fun;
        int fd;

        if (!phb_hash) {
                phb_hash = g_hash_table_new(g_int_hash, g_int_equal);
        }

        if (!host || port <= 0 || !func || strlen(host) > 128) {
                return -1;
        }

        phb = g_new0(struct PHB, 1);
        phb->func = func;
        phb->data = data;

        if (proxyhost[0] && proxyport > 0 && proxytype >= 0 && proxytype < G_N_ELEMENTS(proxy_connect_funcs_array)) {
                fun = proxy_connect_funcs_array[proxytype];
        } else {
                fun = proxy_connect_none;
        }

        fd = fun(host, port, phb);

        if (fd != -1) {
                g_hash_table_insert(phb_hash, &phb->fd, phb);
        }

        return fd;
}

void proxy_disconnect(int fd)
{
        struct PHB *phb = g_hash_table_lookup(phb_hash, &fd);

        if (!phb) {
                /* not in the early part of the connection - just close the fd */
                closesocket(fd);
                return;
        }

        if (phb->inpa) {
                b_event_remove(phb->inpa);
                phb->inpa = 0;
        }

        /* avoid calling the callback, which might result in double-free */
        phb->func = NULL;

        /* close and free */
        phb_free(phb, FALSE);
}