예제 #1
0
string get_ip_from_name(const string& name)
{
    inet_gethostbyname.lock();
    struct hostent *he = gethostbyname(name.c_str());
    if(!he) {
        inet_gethostbyname.unlock();
        return "";
    }
    struct in_addr a;
    bcopy(he->h_addr, (char *) &a, sizeof(a));
    inet_gethostbyname.unlock();
    return get_addr_str(a);
}
예제 #2
0
static void
server_recv_cb(EV_P_ ev_io *w, int revents)
{
    server_ctx_t *server_ctx = (server_ctx_t *)w;
    struct sockaddr_storage src_addr;
    memset(&src_addr, 0, sizeof(struct sockaddr_storage));

    buffer_t *buf = ss_malloc(sizeof(buffer_t));
    balloc(buf, buf_size);

    socklen_t src_addr_len = sizeof(struct sockaddr_storage);
    unsigned int offset    = 0;

#ifdef MODULE_REDIR
    char control_buffer[64] = { 0 };
    struct msghdr msg;
    memset(&msg, 0, sizeof(struct msghdr));
    struct iovec iov[1];
    struct sockaddr_storage dst_addr;
    memset(&dst_addr, 0, sizeof(struct sockaddr_storage));

    msg.msg_name       = &src_addr;
    msg.msg_namelen    = src_addr_len;
    msg.msg_control    = control_buffer;
    msg.msg_controllen = sizeof(control_buffer);

    iov[0].iov_base = buf->data;
    iov[0].iov_len  = buf_size;
    msg.msg_iov     = iov;
    msg.msg_iovlen  = 1;

    buf->len = recvmsg(server_ctx->fd, &msg, 0);
    if (buf->len == -1) {
        ERROR("[udp] server_recvmsg");
        goto CLEAN_UP;
    } else if (buf->len > packet_size) {
        if (verbose) {
            LOGI("[udp] UDP server_recv_recvmsg fragmentation");
        }
    }

    if (get_dstaddr(&msg, &dst_addr)) {
        LOGE("[udp] unable to get dest addr");
        goto CLEAN_UP;
    }

    src_addr_len = msg.msg_namelen;
#else
    ssize_t r;
    r = recvfrom(server_ctx->fd, buf->data, buf_size,
                 0, (struct sockaddr *)&src_addr, &src_addr_len);

    if (r == -1) {
        // error on recv
        // simply drop that packet
        ERROR("[udp] server_recv_recvfrom");
        goto CLEAN_UP;
    } else if (r > packet_size) {
        if (verbose) {
            LOGI("[udp] server_recv_recvfrom fragmentation");
        }
    }

    buf->len = r;
#endif

    if (verbose) {
        LOGI("[udp] server receive a packet");
    }

#ifdef MODULE_REMOTE
    tx += buf->len;

    int err = server_ctx->crypto->decrypt_all(buf, server_ctx->crypto->cipher, buf_size);
    if (err) {
        // drop the packet silently
        goto CLEAN_UP;
    }
#endif

#ifdef MODULE_LOCAL
#if !defined(MODULE_TUNNEL) && !defined(MODULE_REDIR)
#ifdef __ANDROID__
    tx += buf->len;
#endif
    uint8_t frag = *(uint8_t *)(buf->data + 2);
    offset += 3;
#endif
#endif

    /*
     *
     * SOCKS5 UDP Request
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * SOCKS5 UDP Response
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * shadowsocks UDP Request (before encrypted)
     * +------+----------+----------+----------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +------+----------+----------+----------+
     * |  1   | Variable |    2     | Variable |
     * +------+----------+----------+----------+
     *
     * shadowsocks UDP Response (before encrypted)
     * +------+----------+----------+----------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +------+----------+----------+----------+
     * |  1   | Variable |    2     | Variable |
     * +------+----------+----------+----------+
     *
     * shadowsocks UDP Request and Response (after encrypted)
     * +-------+--------------+
     * |   IV  |    PAYLOAD   |
     * +-------+--------------+
     * | Fixed |   Variable   |
     * +-------+--------------+
     *
     */

#ifdef MODULE_REDIR
    char addr_header[512] = { 0 };
    int addr_header_len   = construct_udprelay_header(&dst_addr, addr_header);

    if (addr_header_len == 0) {
        LOGE("[udp] failed to parse tproxy addr");
        goto CLEAN_UP;
    }

    // reconstruct the buffer
    brealloc(buf, buf->len + addr_header_len, buf_size);
    memmove(buf->data + addr_header_len, buf->data, buf->len);
    memcpy(buf->data, addr_header, addr_header_len);
    buf->len += addr_header_len;

#elif MODULE_TUNNEL

    char addr_header[512] = { 0 };
    char *host            = server_ctx->tunnel_addr.host;
    char *port            = server_ctx->tunnel_addr.port;
    uint16_t port_num     = (uint16_t)atoi(port);
    uint16_t port_net_num = htons(port_num);
    int addr_header_len   = 0;

    struct cork_ip ip;
    if (cork_ip_init(&ip, host) != -1) {
        if (ip.version == 4) {
            // send as IPv4
            struct in_addr host_addr;
            memset(&host_addr, 0, sizeof(struct in_addr));
            int host_len = sizeof(struct in_addr);

            if (dns_pton(AF_INET, host, &host_addr) == -1) {
                FATAL("IP parser error");
            }
            addr_header[addr_header_len++] = 1;
            memcpy(addr_header + addr_header_len, &host_addr, host_len);
            addr_header_len += host_len;
        } else if (ip.version == 6) {
            // send as IPv6
            struct in6_addr host_addr;
            memset(&host_addr, 0, sizeof(struct in6_addr));
            int host_len = sizeof(struct in6_addr);

            if (dns_pton(AF_INET6, host, &host_addr) == -1) {
                FATAL("IP parser error");
            }
            addr_header[addr_header_len++] = 4;
            memcpy(addr_header + addr_header_len, &host_addr, host_len);
            addr_header_len += host_len;
        } else {
            FATAL("IP parser error");
        }
    } else {
        // send as domain
        int host_len = strlen(host);

        addr_header[addr_header_len++] = 3;
        addr_header[addr_header_len++] = host_len;
        memcpy(addr_header + addr_header_len, host, host_len);
        addr_header_len += host_len;
    }
    memcpy(addr_header + addr_header_len, &port_net_num, 2);
    addr_header_len += 2;

    // reconstruct the buffer
    brealloc(buf, buf->len + addr_header_len, buf_size);
    memmove(buf->data + addr_header_len, buf->data, buf->len);
    memcpy(buf->data, addr_header, addr_header_len);
    buf->len += addr_header_len;

#else

    char host[257] = { 0 };
    char port[64]  = { 0 };
    struct sockaddr_storage dst_addr;
    memset(&dst_addr, 0, sizeof(struct sockaddr_storage));

    int addr_header_len = parse_udprelay_header(buf->data + offset, buf->len - offset,
                                                host, port, &dst_addr);
    if (addr_header_len == 0) {
        // error in parse header
        goto CLEAN_UP;
    }

    char *addr_header = buf->data + offset;
#endif

#ifdef MODULE_LOCAL
    char *key = hash_key(server_ctx->remote_addr->sa_family, &src_addr);
#else
    char *key = hash_key(dst_addr.ss_family, &src_addr);
#endif

    struct cache *conn_cache = server_ctx->conn_cache;

    remote_ctx_t *remote_ctx = NULL;
    cache_lookup(conn_cache, key, HASH_KEY_LEN, (void *)&remote_ctx);

    if (remote_ctx != NULL) {
        if (sockaddr_cmp(&src_addr, &remote_ctx->src_addr, sizeof(src_addr))) {
            remote_ctx = NULL;
        }
    }

    // reset the timer
    if (remote_ctx != NULL) {
        ev_timer_again(EV_A_ & remote_ctx->watcher);
    }

    if (remote_ctx == NULL) {
        if (verbose) {
#ifdef MODULE_REDIR
            char src[SS_ADDRSTRLEN];
            char dst[SS_ADDRSTRLEN];
            strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
            strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
            LOGI("[udp] cache miss: %s <-> %s", dst, src);
#else
            LOGI("[udp] cache miss: %s:%s <-> %s", host, port,
                 get_addr_str((struct sockaddr *)&src_addr));
#endif
        }
    } else {
        if (verbose) {
#ifdef MODULE_REDIR
            char src[SS_ADDRSTRLEN];
            char dst[SS_ADDRSTRLEN];
            strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
            strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
            LOGI("[udp] cache hit: %s <-> %s", dst, src);
#else
            LOGI("[udp] cache hit: %s:%s <-> %s", host, port,
                 get_addr_str((struct sockaddr *)&src_addr));
#endif
        }
    }

#ifdef MODULE_LOCAL

#if !defined(MODULE_TUNNEL) && !defined(MODULE_REDIR)
    if (frag) {
        LOGE("[udp] drop a message since frag is not 0, but %d", frag);
        goto CLEAN_UP;
    }
#endif

    const struct sockaddr *remote_addr = server_ctx->remote_addr;
    const int remote_addr_len          = server_ctx->remote_addr_len;

    if (remote_ctx == NULL) {
        // Bind to any port
        int remotefd = create_remote_socket(remote_addr->sa_family == AF_INET6);
        if (remotefd < 0) {
            ERROR("[udp] udprelay bind() error");
            goto CLEAN_UP;
        }
        setnonblocking(remotefd);

#ifdef SO_NOSIGPIPE
        set_nosigpipe(remotefd);
#endif
#ifdef IP_TOS
        // Set QoS flag
        int tos = 46;
        setsockopt(remotefd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
#ifdef SET_INTERFACE
        if (server_ctx->iface) {
            if (setinterface(remotefd, server_ctx->iface) == -1)
                ERROR("setinterface");
        }
#endif

#ifdef __ANDROID__
        if (vpn) {
            if (protect_socket(remotefd) == -1) {
                ERROR("protect_socket");
                close(remotefd);
                goto CLEAN_UP;
            }
        }
#endif

        // Init remote_ctx
        remote_ctx                  = new_remote(remotefd, server_ctx);
        remote_ctx->src_addr        = src_addr;
        remote_ctx->af              = remote_addr->sa_family;
        remote_ctx->addr_header_len = addr_header_len;
        memcpy(remote_ctx->addr_header, addr_header, addr_header_len);

        // Add to conn cache
        cache_insert(conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);

        // Start remote io
        ev_io_start(EV_A_ & remote_ctx->io);
        ev_timer_start(EV_A_ & remote_ctx->watcher);
    }

    if (offset > 0) {
        buf->len -= offset;
        memmove(buf->data, buf->data + offset, buf->len);
    }

    int err = server_ctx->crypto->encrypt_all(buf, server_ctx->crypto->cipher, buf_size);

    if (err) {
        // drop the packet silently
        goto CLEAN_UP;
    }

    if (buf->len > packet_size) {
        if (verbose) {
            LOGI("[udp] server_recv_sendto fragmentation");
        }
    }

    int s = sendto(remote_ctx->fd, buf->data, buf->len, 0, remote_addr, remote_addr_len);

    if (s == -1) {
        ERROR("[udp] server_recv_sendto");
    }

#else

    int cache_hit  = 0;
    int need_query = 0;

    if (buf->len - addr_header_len > packet_size) {
        if (verbose) {
            LOGI("[udp] server_recv_sendto fragmentation");
        }
    }

    if (remote_ctx != NULL) {
        cache_hit = 1;
        // detect destination mismatch
        if (remote_ctx->addr_header_len != addr_header_len
            || memcmp(addr_header, remote_ctx->addr_header, addr_header_len) != 0) {
            if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
                need_query = 1;
            }
        } else {
            memcpy(&dst_addr, &remote_ctx->dst_addr, sizeof(struct sockaddr_storage));
        }
    } else {
        if (dst_addr.ss_family == AF_INET || dst_addr.ss_family == AF_INET6) {
            int remotefd = create_remote_socket(dst_addr.ss_family == AF_INET6);
            if (remotefd != -1) {
                setnonblocking(remotefd);
#ifdef SO_BROADCAST
                set_broadcast(remotefd);
#endif
#ifdef SO_NOSIGPIPE
                set_nosigpipe(remotefd);
#endif
#ifdef IP_TOS
                // Set QoS flag
                int tos = 46;
                setsockopt(remotefd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
#ifdef SET_INTERFACE
                if (server_ctx->iface) {
                    if (setinterface(remotefd, server_ctx->iface) == -1)
                        ERROR("setinterface");
                }
#endif
                remote_ctx                  = new_remote(remotefd, server_ctx);
                remote_ctx->src_addr        = src_addr;
                remote_ctx->server_ctx      = server_ctx;
                remote_ctx->addr_header_len = addr_header_len;
                memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
                memcpy(&remote_ctx->dst_addr, &dst_addr, sizeof(struct sockaddr_storage));
            } else {
                ERROR("[udp] bind() error");
                goto CLEAN_UP;
            }
        }
    }

    if (remote_ctx != NULL && !need_query) {
        size_t addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);
        int s           = sendto(remote_ctx->fd, buf->data + addr_header_len,
                                 buf->len - addr_header_len, 0,
                                 (struct sockaddr *)&dst_addr, addr_len);

        if (s == -1) {
            ERROR("[udp] sendto_remote");
            if (!cache_hit) {
                close_and_free_remote(EV_A_ remote_ctx);
            }
        } else {
            if (!cache_hit) {
                // Add to conn cache
                remote_ctx->af = dst_addr.ss_family;
                char *key = hash_key(remote_ctx->af, &remote_ctx->src_addr);
                cache_insert(server_ctx->conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);

                ev_io_start(EV_A_ & remote_ctx->io);
                ev_timer_start(EV_A_ & remote_ctx->watcher);
            }
        }
    } else {
        struct addrinfo hints;
        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family   = AF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_protocol = IPPROTO_UDP;

        struct query_ctx *query_ctx = new_query_ctx(buf->data + addr_header_len,
                                                    buf->len - addr_header_len);
        query_ctx->server_ctx      = server_ctx;
        query_ctx->addr_header_len = addr_header_len;
        query_ctx->src_addr        = src_addr;
        memcpy(query_ctx->addr_header, addr_header, addr_header_len);

        if (need_query) {
            query_ctx->remote_ctx = remote_ctx;
        }

        struct ResolvQuery *query = resolv_query(host, query_resolve_cb,
                                                 NULL, query_ctx, htons(atoi(port)));
        if (query == NULL) {
            ERROR("[udp] unable to create DNS query");
            close_and_free_query(EV_A_ query_ctx);
            goto CLEAN_UP;
        }
        query_ctx->query = query;
    }
#endif

CLEAN_UP:
    bfree(buf);
    ss_free(buf);
}
예제 #3
0
static void server_recv_cb (EV_P_ ev_io *w, int revents)
{
    struct server_ctx *server_ctx = (struct server_ctx *)w;
    struct sockaddr src_addr;
    char *buf = malloc(BUF_SIZE);

    socklen_t src_addr_len = sizeof(src_addr);
    unsigned int offset = 0;

    ssize_t buf_len = recvfrom(server_ctx->fd, buf, BUF_SIZE, 0, &src_addr, &src_addr_len);

    if (buf_len == -1)
    {
        // error on recv
        // simply drop that packet
        if (verbose)
        {
            ERROR("udprelay_server_recvfrom");
        }
        goto CLEAN_UP;
    }

    if (verbose)
    {
        LOGD("[udp] server receive a packet.");
    }

#ifdef UDPRELAY_REMOTE
    buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
#endif

#ifdef UDPRELAY_LOCAL
#ifndef UDPRELAY_TUNNEL
    uint8_t frag = *(uint8_t*)(buf + 2);
    offset += 3;
#endif
#endif

    /*
     *
     * SOCKS5 UDP Request
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * SOCKS5 UDP Response
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * shadowsocks UDP Request (before encrypted)
     * +------+----------+----------+----------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +------+----------+----------+----------+
     * |  1   | Variable |    2     | Variable |
     * +------+----------+----------+----------+
     *
     * shadowsocks UDP Response (before encrypted)
     * +------+----------+----------+----------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +------+----------+----------+----------+
     * |  1   | Variable |    2     | Variable |
     * +------+----------+----------+----------+
     *
     * shadowsocks UDP Request and Response (after encrypted)
     * +-------+--------------+
     * |   IV  |    PAYLOAD   |
     * +-------+--------------+
     * | Fixed |   Variable   |
     * +-------+--------------+
     *
     */

#ifdef UDPRELAY_TUNNEL
    char addr_header[256] = {0};
    char* host = server_ctx->tunnel_addr.host;
    char* port = server_ctx->tunnel_addr.port;
    int host_len = strlen(host);
    uint16_t port_num = (uint16_t)atoi(port);
    uint16_t port_net_num = htons(port_num);
    int addr_header_len = 2 + host_len + 2;

    // initialize the addr header
    addr_header[0] = 3;
    addr_header[1] = host_len;
    memcpy(addr_header + 2, host, host_len);
    memcpy(addr_header + 2 + host_len, &port_net_num, 2);

    // reconstruct the buffer
    char *tmp = malloc(buf_len + addr_header_len);
    memcpy(tmp, addr_header, addr_header_len);
    memcpy(tmp + addr_header_len, buf, buf_len);
    free(buf);
    buf = tmp;
    buf_len += addr_header_len;

#else
    char host[256] = {0};
    char port[64] = {0};

    int addr_header_len = parse_udprealy_header(buf + offset,
                          buf_len - offset, host, port);
    if (addr_header_len == 0)
    {
        // error in parse header
        goto CLEAN_UP;
    }
    char *addr_header = buf + offset;
#endif

    char *key = hash_key(addr_header, addr_header_len, &src_addr);
    struct cache *conn_cache = server_ctx->conn_cache;

    struct remote_ctx *remote_ctx = NULL;
    cache_lookup(conn_cache, key, (void*)&remote_ctx);

    if (remote_ctx != NULL)
    {
        if (memcmp(&src_addr, &remote_ctx->src_addr, sizeof(src_addr))
                || strcmp(addr_header, remote_ctx->addr_header) != 0)
        {
            remote_ctx = NULL;
        }
    }

    if (remote_ctx == NULL)
    {
        if (verbose)
        {
            LOGD("[udp] cache missed: %s:%s <-> %s", host, port, get_addr_str(&src_addr));
        }
    }
    else
    {
        if (verbose)
        {
            LOGD("[udp] cache hit: %s:%s <-> %s", host, port, get_addr_str(&src_addr));
        }
    }

#ifdef UDPRELAY_LOCAL

#ifndef UDPRELAY_TUNNEL
    if (frag)
    {
        LOGE("drop a message since frag is not 0, but %d", frag);
        goto CLEAN_UP;
    }
#endif

    if (remote_ctx == NULL)
    {
        struct addrinfo hints;
        struct addrinfo *result;

        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = AF_UNSPEC; /* Return IPv4 and IPv6 choices */
        hints.ai_socktype = SOCK_DGRAM; /* We want a UDP socket */

        int s = getaddrinfo(server_ctx->remote_host, server_ctx->remote_port,
                            &hints, &result);
        if (s != 0 || result == NULL)
        {
            LOGE("getaddrinfo: %s", gai_strerror(s));
            goto CLEAN_UP;
        }

        // Bind to any port
        int remotefd = create_remote_socket(result->ai_family == AF_INET6);
        if (remotefd < 0)
        {
            ERROR("udprelay bind() error..");
            // remember to free addrinfo
            freeaddrinfo(result);
            goto CLEAN_UP;
        }
        setnonblocking(remotefd);

#ifdef SO_NOSIGPIPE
        int opt = 1;
        setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
#ifdef SET_INTERFACE
        if (server_ctx->iface)
            setinterface(remotefd, server_ctx->iface);
#endif

        // Init remote_ctx
        remote_ctx = new_remote(remotefd, server_ctx);
        remote_ctx->src_addr = src_addr;
        remote_ctx->dst_addr = *result->ai_addr;
        remote_ctx->addr_header_len = addr_header_len;
        memcpy(remote_ctx->addr_header, addr_header, addr_header_len);

        // Add to conn cache
        cache_insert(conn_cache, key, (void *)remote_ctx);

        // Start remote io
        ev_io_start(EV_A_ &remote_ctx->io);

        // clean up
        freeaddrinfo(result);
    }

    if (offset > 0)
    {
        buf_len -= offset;
        memmove(buf, buf + offset, buf_len);
    }

    buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);

    int s = sendto(remote_ctx->fd, buf, buf_len, 0, &remote_ctx->dst_addr, sizeof(remote_ctx->dst_addr));

    if (s == -1)
    {
        ERROR("udprelay_sendto_remote");
    }

#else

    if (remote_ctx == NULL)
    {
        struct addrinfo hints;
        asyncns_query_t *query;
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        query = asyncns_getaddrinfo(server_ctx->asyncns,
                                    host, port, &hints);

        if (query == NULL)
        {
            ERROR("udp_asyncns_getaddrinfo");
            goto CLEAN_UP;
        }

        struct query_ctx *query_ctx = new_query_ctx(query, buf + addr_header_len,
                buf_len - addr_header_len);
        query_ctx->server_ctx = server_ctx;
        query_ctx->addr_header_len = addr_header_len;
        query_ctx->src_addr = src_addr;
        memcpy(query_ctx->addr_header, addr_header, addr_header_len);

        ev_timer_start(EV_A_ &query_ctx->watcher);

    }
    else
    {
        int s = sendto(remote_ctx->fd, buf + addr_header_len,
                buf_len - addr_header_len, 0, &remote_ctx->dst_addr, sizeof(remote_ctx->dst_addr));

        if (s == -1)
        {
            ERROR("udprelay_sendto_remote");
        }
    }
#endif

CLEAN_UP:
    free(buf);

}
예제 #4
0
static void remote_recv_cb(EV_P_ ev_io *w, int revents)
{
    ssize_t r;
    remote_ctx_t *remote_ctx = (remote_ctx_t *)w;
    server_ctx_t *server_ctx = remote_ctx->server_ctx;

    // server has been closed
    if (server_ctx == NULL) {
        LOGE("[udp] invalid server");
        close_and_free_remote(EV_A_ remote_ctx);
        return;
    }

    struct sockaddr_storage src_addr;
    socklen_t src_addr_len = sizeof(src_addr);
    memset(&src_addr, 0, src_addr_len);

    buffer_t *buf = ss_malloc(sizeof(buffer_t));
    balloc(buf, buf_size1);

    // recv
    r = recvfrom(remote_ctx->fd, buf->array, buf_size1, 0, (struct sockaddr *)&src_addr, &src_addr_len);

    if (r == -1) {
        // error on recv
        // simply drop that packet
        ERROR("[udp] remote_recv_recvfrom");
        goto CLEAN_UP;
    } else if (r > packet_size) {
        LOGE("[udp] remote_recv_recvfrom fragmentation");
        goto CLEAN_UP;
    }

    buf->len = r;

#ifdef MODULE_LOCAL
    int err = ss_decrypt_all(buf, server_ctx->method, 0, buf_size1);
    if (err) {
        // drop the packet silently
        goto CLEAN_UP;
    }

#ifdef MODULE_REDIR
    struct sockaddr_storage dst_addr;
    memset(&dst_addr, 0, sizeof(struct sockaddr_storage));
    int len = parse_udprealy_header(buf->array, buf->len, NULL, NULL, NULL, &dst_addr);

    if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
        LOGI("[udp] ss-redir does not support domain name");
        goto CLEAN_UP;
    }

    if (verbose) {
        char src[SS_ADDRSTRLEN];
        char dst[SS_ADDRSTRLEN];
        strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
        strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
        LOGI("[udp] recv %s via %s", dst, src);
    }
#else
    int len = parse_udprealy_header(buf->array, buf->len, NULL, NULL, NULL, NULL);
#endif

    if (len == 0) {
        LOGI("[udp] error in parse header");
        // error in parse header
        goto CLEAN_UP;
    }

    // server may return using a different address type other than the type we
    // have used during sending

#if defined(MODULE_TUNNEL) || defined(MODULE_REDIR)
    // Construct packet
    buf->len -= len;
    memmove(buf->array, buf->array + len, buf->len);
#else
    // Construct packet
    brealloc(buf, buf->len + 3, buf_size1);
    memmove(buf->array + 3, buf->array, buf->len);
    memset(buf->array, 0, 3);
    buf->len += 3;
#endif
#endif

#ifdef MODULE_REMOTE

    rx += buf->len;

    char addr_header_buf[512];
    char *addr_header   = remote_ctx->addr_header;
    int addr_header_len = remote_ctx->addr_header_len;

    if (remote_ctx->af == AF_INET || remote_ctx->af == AF_INET6) {
        addr_header_len = construct_udprealy_header(&src_addr, addr_header_buf);
        addr_header     = addr_header_buf;
    }

    // Construct packet
    brealloc(buf, buf->len + addr_header_len, buf_size);
    memmove(buf->array + addr_header_len, buf->array, buf->len);
    memcpy(buf->array, addr_header, addr_header_len);
    buf->len += addr_header_len;

    int err = ss_encrypt_all(buf, server_ctx->method, 0, buf_size);
    if (err) {
        // drop the packet silently
        goto CLEAN_UP;
    }
#endif

    if (buf->len > packet_size) {
        LOGE("[udp] remote_recv_sendto fragmentation");
        goto CLEAN_UP;
    }

    size_t remote_src_addr_len = get_sockaddr_len((struct sockaddr *)&remote_ctx->src_addr);

#ifdef MODULE_REDIR
    size_t remote_dst_addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);

    int src_fd = socket(remote_ctx->src_addr.ss_family, SOCK_DGRAM, 0);
    if (src_fd < 0) {
        ERROR("[udp] remote_recv_socket");
        goto CLEAN_UP;
    }
    int opt = 1;
    if (setsockopt(src_fd, SOL_IP, IP_TRANSPARENT, &opt, sizeof(opt))) {
        ERROR("[udp] remote_recv_setsockopt");
        close(src_fd);
        goto CLEAN_UP;
    }
    if (setsockopt(src_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) {
        ERROR("[udp] remote_recv_setsockopt");
        close(src_fd);
        goto CLEAN_UP;
    }
#ifdef IP_TOS
    // Set QoS flag
    int tos = 46;
    setsockopt(src_fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
    if (bind(src_fd, (struct sockaddr *)&dst_addr, remote_dst_addr_len) != 0) {
        ERROR("[udp] remote_recv_bind");
        close(src_fd);
        goto CLEAN_UP;
    }

    int s = sendto(src_fd, buf->array, buf->len, 0,
                   (struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
    if (s == -1) {
        ERROR("[udp] remote_recv_sendto");
        close(src_fd);
        goto CLEAN_UP;
    }
    close(src_fd);

#else
    int s = sendto(server_ctx->fd, buf->array, buf->len, 0,
                   (struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
    if (s == -1) {
        ERROR("[udp] remote_recv_sendto");
        goto CLEAN_UP;
    }
#endif

    // handle the UDP packet successfully,
    // triger the timer
    ev_timer_again(EV_A_ & remote_ctx->watcher);

CLEAN_UP:

    bfree(buf);
    ss_free(buf);
}
예제 #5
0
static void server_recv_cb(EV_P_ ev_io *w, int revents)
{
    struct server_ctx *server_ctx = (struct server_ctx *)w;
    struct sockaddr_storage src_addr;
    memset(&src_addr, 0, sizeof(struct sockaddr_storage));
    char *buf = malloc(BUF_SIZE);

    socklen_t src_addr_len = sizeof(struct sockaddr_storage);
    unsigned int offset = 0;

#ifdef UDPRELAY_REDIR
    char control_buffer[64] = { 0 };
    struct msghdr msg;
    struct iovec iov[1];
    struct sockaddr_storage dst_addr;
    memset(&dst_addr, 0, sizeof(struct sockaddr_storage));

    msg.msg_name = &src_addr;
    msg.msg_namelen = src_addr_len;
    msg.msg_control = control_buffer;
    msg.msg_controllen = sizeof(control_buffer);

    iov[0].iov_base = buf;
    iov[0].iov_len = BUF_SIZE;
    msg.msg_iov = iov;
    msg.msg_iovlen = 1;

    ssize_t buf_len = recvmsg(server_ctx->fd, &msg, 0);
    if (buf_len == -1) {
        ERROR("[udp] server_recvmsg");
        goto CLEAN_UP;
    }

    if (get_dstaddr(&msg, &dst_addr)) {
        LOGE("[udp] unable to get dest addr");
        goto CLEAN_UP;
    }

    src_addr_len = msg.msg_namelen;
#else
    ssize_t buf_len =
        recvfrom(server_ctx->fd, buf, BUF_SIZE, 0, (struct sockaddr *)&src_addr,
                 &src_addr_len);

    if (buf_len == -1) {
        // error on recv
        // simply drop that packet
        ERROR("[udp] server_recvfrom");
        goto CLEAN_UP;
    }
#endif

    if (verbose) {
        LOGI("[udp] server receive a packet");
    }

#ifdef UDPRELAY_REMOTE

    tx += buf_len;

    buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method, server_ctx->auth);
    if (buf == NULL) {
        ERROR("[udp] server_ss_decrypt_all");
        goto CLEAN_UP;
    }
#endif

#ifdef UDPRELAY_LOCAL
#if !defined(UDPRELAY_TUNNEL) && !defined(UDPRELAY_REDIR)
    uint8_t frag = *(uint8_t *)(buf + 2);
    offset += 3;
#endif
#endif

    // packet size > default MTU
    if (verbose && buf_len > MTU) {
        LOGE("[udp] possible ip fragment, size: %d", (int)buf_len);
    }

    /*
     *
     * SOCKS5 UDP Request
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * SOCKS5 UDP Response
     * +----+------+------+----------+----------+----------+
     * |RSV | FRAG | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +----+------+------+----------+----------+----------+
     * | 2  |  1   |  1   | Variable |    2     | Variable |
     * +----+------+------+----------+----------+----------+
     *
     * shadowsocks UDP Request (before encrypted)
     * +------+----------+----------+----------+-------------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |  HMAC-SHA1  |
     * +------+----------+----------+----------+-------------+
     * |  1   | Variable |    2     | Variable |     10      |
     * +------+----------+----------+----------+-------------+
     *
     * If ATYP & ONETIMEAUTH_FLAG(0x10) == 1, Authentication (HMAC-SHA1) is enabled.
     *
     * The key of HMAC-SHA1 is (IV + KEY) and the input is the whole packet.
     * The output of HMAC-SHA is truncated to 10 bytes (leftmost bits).
     *
     * shadowsocks UDP Response (before encrypted)
     * +------+----------+----------+----------+
     * | ATYP | DST.ADDR | DST.PORT |   DATA   |
     * +------+----------+----------+----------+
     * |  1   | Variable |    2     | Variable |
     * +------+----------+----------+----------+
     *
     * shadowsocks UDP Request and Response (after encrypted)
     * +-------+--------------+
     * |   IV  |    PAYLOAD   |
     * +-------+--------------+
     * | Fixed |   Variable   |
     * +-------+--------------+
     *
     */

#ifdef UDPRELAY_REDIR
    char addr_header[256] = { 0 };
    int addr_header_len = construct_udprealy_header(&dst_addr, addr_header);

    if (addr_header_len == 0) {
        LOGE("[udp] failed to parse tproxy addr");
        goto CLEAN_UP;
    }

    // reconstruct the buffer
    if (BUF_SIZE < buf_len + addr_header_len) {
        buf = realloc(buf, buf_len + addr_header_len);
    }
    memmove(buf + addr_header_len, buf, buf_len);
    memcpy(buf, addr_header, addr_header_len);
    buf_len += addr_header_len;

    char *key = hash_key(dst_addr.ss_family, &src_addr);

#elif UDPRELAY_TUNNEL

    char addr_header[256] = { 0 };
    char *host = server_ctx->tunnel_addr.host;
    char *port = server_ctx->tunnel_addr.port;
    uint16_t port_num = (uint16_t)atoi(port);
    uint16_t port_net_num = htons(port_num);
    int addr_header_len = 0;

    struct cork_ip ip;
    if (cork_ip_init(&ip, host) != -1) {
        if (ip.version == 4) {
            // send as IPv4
            struct in_addr host_addr;
            int host_len = sizeof(struct in_addr);

            if (dns_pton(AF_INET, host, &host_addr) == -1) {
                FATAL("IP parser error");
            }
            addr_header[addr_header_len++] = 1;
            memcpy(addr_header + addr_header_len, &host_addr, host_len);
            addr_header_len += host_len;
        } else if (ip.version == 6) {
            // send as IPv6
            struct in6_addr host_addr;
            int host_len = sizeof(struct in6_addr);

            if (dns_pton(AF_INET6, host, &host_addr) == -1) {
                FATAL("IP parser error");
            }
            addr_header[addr_header_len++] = 4;
            memcpy(addr_header + addr_header_len, &host_addr, host_len);
            addr_header_len += host_len;
        } else {
            FATAL("IP parser error");
        }
    } else {
        // send as domain
        int host_len = strlen(host);

        addr_header[addr_header_len++] = 3;
        addr_header[addr_header_len++] = host_len;
        memcpy(addr_header + addr_header_len, host, host_len);
        addr_header_len += host_len;
    }
    memcpy(addr_header + addr_header_len, &port_net_num, 2);
    addr_header_len += 2;

    // reconstruct the buffer
    if (BUF_SIZE < buf_len + addr_header_len) {
        buf = realloc(buf, buf_len + addr_header_len);
    }
    memmove(buf + addr_header_len, buf, buf_len);
    memcpy(buf, addr_header, addr_header_len);
    buf_len += addr_header_len;

    char *key = hash_key(ip.version == 4 ? AF_INET : AF_INET6, &src_addr);

#else

    char host[256] = { 0 };
    char port[64] = { 0 };
    struct sockaddr_storage dst_addr;
    memset(&dst_addr, 0, sizeof(struct sockaddr_storage));

    int addr_header_len = parse_udprealy_header(buf + offset, buf_len - offset,
                                                &server_ctx->auth, host, port,
                                                &dst_addr);
    if (addr_header_len == 0) {
        // error in parse header
        goto CLEAN_UP;
    }
    char *addr_header = buf + offset;

    char *key = hash_key(dst_addr.ss_family, &src_addr);
#endif

    struct cache *conn_cache = server_ctx->conn_cache;

    struct remote_ctx *remote_ctx = NULL;
    cache_lookup(conn_cache, key, HASH_KEY_LEN, (void *)&remote_ctx);

    if (remote_ctx != NULL) {
        if (memcmp(&src_addr, &remote_ctx->src_addr, sizeof(src_addr))) {
            remote_ctx = NULL;
        }
    }

    // reset the timer
    if (remote_ctx != NULL) {
        ev_timer_again(EV_A_ & remote_ctx->watcher);
    }

    if (remote_ctx == NULL) {
        if (verbose) {
#ifdef UDPRELAY_REDIR
            char src[SS_ADDRSTRLEN];
            char dst[SS_ADDRSTRLEN];
            strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
            strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
            LOGI("[udp] cache miss: %s <-> %s", dst, src);
#else
            LOGI("[udp] cache miss: %s:%s <-> %s", host, port,
                 get_addr_str((struct sockaddr *)&src_addr));
#endif
        }
    } else {
        if (verbose) {
#ifdef UDPRELAY_REDIR
            char src[SS_ADDRSTRLEN];
            char dst[SS_ADDRSTRLEN];
            strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
            strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
            LOGI("[udp] cache hit: %s <-> %s", dst, src);
#else
            LOGI("[udp] cache hit: %s:%s <-> %s", host, port,
                 get_addr_str((struct sockaddr *)&src_addr));
#endif
        }
    }

#ifdef UDPRELAY_LOCAL

#if !defined(UDPRELAY_TUNNEL) && !defined(UDPRELAY_REDIR)
    if (frag) {
        LOGE("[udp] drop a message since frag is not 0, but %d", frag);
        goto CLEAN_UP;
    }
#endif

    const struct sockaddr *remote_addr = server_ctx->remote_addr;
    const int remote_addr_len = server_ctx->remote_addr_len;

    if (remote_ctx == NULL) {
        // Bind to any port
        int remotefd = create_remote_socket(remote_addr->sa_family == AF_INET6);
        if (remotefd < 0) {
            ERROR("[udp] udprelay bind() error");
            goto CLEAN_UP;
        }
        setnonblocking(remotefd);

#ifdef SO_NOSIGPIPE
        set_nosigpipe(remotefd);
#endif
#ifdef SET_INTERFACE
        if (server_ctx->iface) {
            setinterface(remotefd, server_ctx->iface);
        }
#endif

#ifdef ANDROID
        if (vpn) {
            if (protect_socket(remotefd) == -1) {
                ERROR("protect_socket");
                close(remotefd);
                goto CLEAN_UP;
            }
        }
#endif

        // Init remote_ctx
        remote_ctx = new_remote(remotefd, server_ctx);
        remote_ctx->src_addr = src_addr;
        remote_ctx->af = remote_addr->sa_family;
        remote_ctx->addr_header_len = addr_header_len;
        memcpy(remote_ctx->addr_header, addr_header, addr_header_len);

        // Add to conn cache
        cache_insert(conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);

        // Start remote io
        ev_io_start(EV_A_ & remote_ctx->io);
        ev_timer_start(EV_A_ & remote_ctx->watcher);

    }

    if (offset > 0) {
        buf_len -= offset;
        memmove(buf, buf + offset, buf_len);
    }

    if (server_ctx->auth) {
        buf[0] |= ONETIMEAUTH_FLAG;
    }

    buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method, server_ctx->auth);

    int s = sendto(remote_ctx->fd, buf, buf_len, 0, remote_addr, remote_addr_len);

    if (s == -1) {
        ERROR("[udp] sendto_remote");
    }

#else

    int cache_hit = 0;
    int need_query = 0;

    if (remote_ctx != NULL) {
        cache_hit = 1;
        // detect destination mismatch
        if (remote_ctx->addr_header_len != addr_header_len
                || memcmp(addr_header, remote_ctx->addr_header, addr_header_len) != 0) {
            if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
                need_query = 1;
            }
        }
    } else {
        if (dst_addr.ss_family == AF_INET || dst_addr.ss_family == AF_INET6) {
            int remotefd = create_remote_socket(dst_addr.ss_family == AF_INET6);
            if (remotefd != -1) {
                setnonblocking(remotefd);
#ifdef SO_BROADCAST
                set_broadcast(remotefd);
#endif
#ifdef SO_NOSIGPIPE
                set_nosigpipe(remotefd);
#endif
#ifdef SET_INTERFACE
                if (server_ctx->iface) {
                    setinterface(remotefd, server_ctx->iface);
                }
#endif
                remote_ctx = new_remote(remotefd, server_ctx);
                remote_ctx->src_addr = src_addr;
                remote_ctx->server_ctx = server_ctx;
                remote_ctx->addr_header_len = addr_header_len;
                memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
            } else {
                ERROR("[udp] bind() error");
                goto CLEAN_UP;
            }
        }
    }

    if (remote_ctx != NULL && !need_query) {
        size_t addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);
        int s = sendto(remote_ctx->fd, buf + addr_header_len,
                buf_len - addr_header_len, 0,
                (struct sockaddr *)&dst_addr, addr_len);

        if (s == -1) {
            ERROR("[udp] sendto_remote");
            if (!cache_hit) {
                close_and_free_remote(EV_A_ remote_ctx);
            }
        } else {
            if (!cache_hit) {
                // Add to conn cache
                remote_ctx->af = dst_addr.ss_family;
                char *key = hash_key(remote_ctx->af, &remote_ctx->src_addr);
                cache_insert(server_ctx->conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);

                ev_io_start(EV_A_ & remote_ctx->io);
                ev_timer_start(EV_A_ & remote_ctx->watcher);
            }
        }
    } else {
        struct addrinfo hints;
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_protocol = IPPROTO_UDP;

        struct query_ctx *query_ctx = new_query_ctx(buf + addr_header_len,
                buf_len -
                addr_header_len);
        query_ctx->server_ctx = server_ctx;
        query_ctx->addr_header_len = addr_header_len;
        query_ctx->src_addr = src_addr;
        memcpy(query_ctx->addr_header, addr_header, addr_header_len);

        if (need_query) {
            query_ctx->remote_ctx = remote_ctx;
        }

        struct ResolvQuery *query = resolv_query(host, query_resolve_cb,
                NULL, query_ctx, htons(atoi(port)));
        if (query == NULL) {
            ERROR("[udp] unable to create DNS query");
            close_and_free_query(EV_A_ query_ctx);
            goto CLEAN_UP;
        }
        query_ctx->query = query;
    }
#endif

 CLEAN_UP:
    free(buf);
}
예제 #6
0
int trans_layer::cancel(trans_bucket* bucket, sip_trans* t)
{
    bucket->lock();
    if(!bucket->exist(t)){
	DBG("No transaction to cancel: wrong key or finally replied\n");
	bucket->unlock();
	return 0;
    }

    sip_msg* req = t->msg;
    
    // RFC 3261 says: SHOULD NOT be sent for other request
    // than INVITE.
    if(req->u.request->method != sip_request::INVITE){
	bucket->unlock();
	ERROR("Trying to cancel a non-INVITE request (we SHOULD NOT do that)\n");
	return -1;
    }
    
    switch(t->state){
    case TS_CALLING:
	// do not send a request:
	// just remove the transaction
	bucket->remove_trans(t);
	bucket->unlock();
	return 0;

    case TS_COMPLETED:
	// final reply has been sent:
	// do nothing!!!
	bucket->unlock();
	return 0;
	
    case TS_PROCEEDING:
	// continue with CANCEL request
	break;
    }

    cstring cancel_str("CANCEL");

    int request_len = request_line_len(cancel_str,
				       req->u.request->ruri_str);

    char branch_buf[BRANCH_BUF_LEN];
    compute_branch(branch_buf,req->callid->value,get_cseq(req)->num_str);
    cstring branch(branch_buf,BRANCH_BUF_LEN);
    
    string via(transport->get_local_ip());
    if(transport->get_local_port() != 5060)
	via += ":" + int2str(transport->get_local_port());

    request_len += copy_hdr_len(req->via1);

    request_len += copy_hdr_len(req->to)
	+ copy_hdr_len(req->from)
	+ copy_hdr_len(req->callid)
	+ cseq_len(get_cseq(req)->num_str,cancel_str)
	+ copy_hdrs_len(req->route)
	+ copy_hdrs_len(req->contacts);

    request_len += 2/* CRLF end-of-headers*/;

    // Allocate new message
    sip_msg* p_msg = new sip_msg();
    p_msg->buf = new char[request_len];
    p_msg->len = request_len;

    // generate it
    char* c = p_msg->buf;
    request_line_wr(&c,cancel_str,
		    req->u.request->ruri_str);

    copy_hdr_wr(&c,req->via1);
    copy_hdr_wr(&c,req->to);
    copy_hdr_wr(&c,req->from);
    copy_hdr_wr(&c,req->callid);
    cseq_wr(&c,get_cseq(req)->num_str,cancel_str);
    copy_hdrs_wr(&c,req->route);
    copy_hdrs_wr(&c,req->contacts);

    *c++ = CR;
    *c++ = LF;

    // and parse it
    if(parse_sip_msg(p_msg)){
	ERROR("Parser failed on generated request\n");
	ERROR("Message was: <%.*s>\n",p_msg->len,p_msg->buf);
	delete p_msg;
	return MALFORMED_SIP_MSG;
    }

    memcpy(&p_msg->remote_ip,&req->remote_ip,sizeof(sockaddr_storage));

    DBG("Sending to %s:%i <%.*s>\n",
	get_addr_str(((sockaddr_in*)&p_msg->remote_ip)->sin_addr).c_str(),
	ntohs(((sockaddr_in*)&p_msg->remote_ip)->sin_port),
	p_msg->len,p_msg->buf);

    int send_err = transport->send(&p_msg->remote_ip,p_msg->buf,p_msg->len);
    if(send_err < 0){
	ERROR("Error from transport layer\n");
	delete p_msg;
    }
    else {
	trans_bucket* n_bucket = get_trans_bucket(p_msg->callid->value,
						  get_cseq(p_msg)->num_str);

	if(bucket != n_bucket)
	    n_bucket->lock();

	sip_trans* t = n_bucket->add_trans(p_msg,TT_UAC);
	    
	// if transport == UDP
	t->reset_timer(STIMER_E,E_TIMER,bucket->get_id());
	// for any transport type
	t->reset_timer(STIMER_F,F_TIMER,bucket->get_id());

	if(bucket != n_bucket)
	    n_bucket->unlock();
    }
    
    bucket->unlock();
    return send_err;
}
예제 #7
0
int trans_layer::send_request(sip_msg* msg, char* tid, unsigned int& tid_len)
{
    // Request-URI
    // To
    // From
    // Call-ID
    // CSeq
    // Max-Forwards
    // Via
    // Contact
    // Supported / Require
    // Content-Length / Content-Type
    
    assert(transport);

    tid_len = 0;

    if(set_next_hop(msg->route,msg->u.request->ruri_str,
		    &msg->remote_ip) < 0){
	// TODO: error handling
	DBG("set_next_hop failed\n");
	//delete msg;
	return -1;
    }

    // assume that msg->route headers are not in msg->hdrs
    msg->hdrs.insert(msg->hdrs.begin(),msg->route.begin(),msg->route.end());

    int request_len = request_line_len(msg->u.request->method_str,
				       msg->u.request->ruri_str);

    char branch_buf[BRANCH_BUF_LEN];
    compute_branch(branch_buf,msg->callid->value,msg->cseq->value);
    cstring branch(branch_buf,BRANCH_BUF_LEN);
    
    string via(transport->get_local_ip());
    if(transport->get_local_port() != 5060)
	via += ":" + int2str(transport->get_local_port());

    request_len += via_len(stl2cstr(via),branch);

    request_len += copy_hdrs_len(msg->hdrs);

    string content_len = int2str(msg->body.len);

    request_len += content_length_len(stl2cstr(content_len));
    request_len += 2/* CRLF end-of-headers*/;

    if(msg->body.len){
	request_len += msg->body.len;
    }

    // Allocate new message
    sip_msg* p_msg = new sip_msg();
    p_msg->buf = new char[request_len];
    p_msg->len = request_len;

    // generate it
    char* c = p_msg->buf;
    request_line_wr(&c,msg->u.request->method_str,
		    msg->u.request->ruri_str);

    via_wr(&c,stl2cstr(via),branch);
    copy_hdrs_wr(&c,msg->hdrs);

    content_length_wr(&c,stl2cstr(content_len));

    *c++ = CR;
    *c++ = LF;

    if(msg->body.len){
	memcpy(c,msg->body.s,msg->body.len);

	// Not needed by now as the message is finished
	//c += body.len;
    }

    // and parse it
    if(parse_sip_msg(p_msg)){
	ERROR("Parser failed on generated request\n");
	ERROR("Message was: <%.*s>\n",p_msg->len,p_msg->buf);
	delete p_msg;
	return MALFORMED_SIP_MSG;
    }

    memcpy(&p_msg->remote_ip,&msg->remote_ip,sizeof(sockaddr_storage));

    DBG("Sending to %s:%i <%.*s>\n",
	get_addr_str(((sockaddr_in*)&p_msg->remote_ip)->sin_addr).c_str(),
	ntohs(((sockaddr_in*)&p_msg->remote_ip)->sin_port),
	p_msg->len,p_msg->buf);

    trans_bucket* bucket = get_trans_bucket(p_msg->callid->value,
					    get_cseq(p_msg)->num_str);
    bucket->lock();

    int send_err = transport->send(&p_msg->remote_ip,p_msg->buf,p_msg->len);
    if(send_err < 0){
	ERROR("Error from transport layer\n");
	delete p_msg;
    }
    else {

	sip_trans* t = bucket->add_trans(p_msg,TT_UAC);
	if(p_msg->u.request->method == sip_request::INVITE){
	    
	    // if transport == UDP
	    t->reset_timer(STIMER_A,A_TIMER,bucket->get_id());
	    // for any transport type
	    t->reset_timer(STIMER_B,B_TIMER,bucket->get_id());
	}
	else {
	    
	    // if transport == UDP
	    t->reset_timer(STIMER_E,E_TIMER,bucket->get_id());
	    // for any transport type
	    t->reset_timer(STIMER_F,F_TIMER,bucket->get_id());

	}

	string t_id = int2hex(bucket->get_id()).substr(5,string::npos) 
	    + ":" + long2hex((unsigned long)t);
	memcpy(tid,t_id.c_str(),t_id.length());
	tid_len = t_id.length();
    }

    bucket->unlock();
    
    return send_err;
}