* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) Jeremy Harris 2015 */
+/* Copyright (c) The Exim Maintainers 2021 - 2022 */
+/* Copyright (c) Jeremy Harris 2015 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-only */
/* SOCKS version 5 proxy, client-mode */
#include "../exim.h"
#include "smtp.h"
-#ifdef EXPERIMENTAL_SOCKS /* entire file */
+#ifdef SUPPORT_SOCKS /* entire file */
#ifndef nelem
# define nelem(arr) (sizeof(arr)/sizeof(*arr))
/* Defaults */
#define SOCKS_PORT 1080
#define SOCKS_TIMEOUT 5
+#define SOCKS_WEIGHT 1
+#define SOCKS_PRIORITY 1
#define AUTH_NONE 0
#define AUTH_NAME 2 /* user/password per RFC 1929 */
typedef struct
{
+ const uschar * proxy_host;
uschar auth_type; /* RFC 1928 encoding */
const uschar * auth_name;
const uschar * auth_pwd;
short port;
+ BOOL is_failed;
unsigned timeout;
+ unsigned weight;
+ unsigned priority;
} socks_opts;
static void
socks_option_defaults(socks_opts * sob)
{
-sob->auth_type = AUTH_NONE;
-sob->auth_name = US"";
-sob->auth_pwd = US"";
-sob->port = SOCKS_PORT;
-sob->timeout = SOCKS_TIMEOUT;
+sob->proxy_host = NULL;
+sob->auth_type = AUTH_NONE;
+sob->auth_name = US"";
+sob->auth_pwd = US"";
+sob->is_failed = FALSE;
+sob->port = SOCKS_PORT;
+sob->timeout = SOCKS_TIMEOUT;
+sob->weight = SOCKS_WEIGHT;
+sob->priority = SOCKS_PRIORITY;
}
static void
socks_option(socks_opts * sob, const uschar * opt)
{
-const uschar * s;
-
if (Ustrncmp(opt, "auth=", 5) == 0)
{
opt += 5;
else if (Ustrncmp(opt, "pass=", 5) == 0)
sob->auth_pwd = opt + 5;
else if (Ustrncmp(opt, "port=", 5) == 0)
- sob->port = atoi(opt + 5);
+ sob->port = atoi(CCS opt + 5);
else if (Ustrncmp(opt, "tmo=", 4) == 0)
- sob->timeout = atoi(opt + 4);
+ sob->timeout = atoi(CCS opt + 4);
+else if (Ustrncmp(opt, "pri=", 4) == 0)
+ sob->priority = atoi(CCS opt + 4);
+else if (Ustrncmp(opt, "weight=", 7) == 0)
+ sob->weight = atoi(CCS opt + 7);
return;
}
case AUTH_NONE:
return OK;
case AUTH_NAME:
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" socks auth NAME '%s' '%s'\n",
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" socks auth NAME '%s' '%s'\n",
sob->auth_name, sob->auth_pwd);
i = Ustrlen(sob->auth_name);
j = Ustrlen(sob->auth_pwd);
len = i + j + 3;
HDEBUG(D_transport|D_acl|D_v)
{
- int i;
- debug_printf(" SOCKS>>");
- for (i = 0; i<len; i++) debug_printf(" %02x", s[i]);
+ debug_printf_indent(" SOCKS>>");
+ for (int i = 0; i<len; i++) debug_printf(" %02x", s[i]);
debug_printf("\n");
}
- if ( send(fd, s, len, 0) < 0
- || !fd_ready(fd, tmo-time(NULL))
- || read(fd, s, 2) != 2
- )
+ if (send(fd, s, len, 0) < 0)
+ return FAIL;
+#ifdef TCP_QUICKACK
+ (void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
+ if (!fd_ready(fd, tmo) || read(fd, s, 2) != 2)
return FAIL;
HDEBUG(D_transport|D_acl|D_v)
- debug_printf(" SOCKS<< %02x %02x\n", s[0], s[1]);
+ debug_printf_indent(" SOCKS<< %02x %02x\n", s[0], s[1]);
if (s[0] == AUTH_NAME_VER && s[1] == 0)
{
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" socks auth OK\n");
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" socks auth OK\n");
return OK;
}
+/* Find a suitable proxy to use from the list.
+Possible common code with spamd_get_server() ?
+
+Return: index into proxy spec array, or -1
+*/
+
+static int
+socks_get_proxy(socks_opts * proxies, unsigned nproxies)
+{
+unsigned int i;
+socks_opts * sd;
+socks_opts * lim = &proxies[nproxies];
+long rnd, weights;
+unsigned pri;
+
+if (nproxies == 1) /* shortcut, if we have only 1 server */
+ return (proxies[0].is_failed ? -1 : 0);
+
+/* scan for highest pri */
+for (pri = 0, sd = proxies; sd < lim; sd++)
+ if (!sd->is_failed && sd->priority > pri)
+ pri = sd->priority;
+
+/* get sum of weights at this pri */
+for (weights = 0, sd = proxies; sd < lim; sd++)
+ if (!sd->is_failed && sd->priority == pri)
+ weights += sd->weight;
+if (weights == 0) /* all servers failed */
+ return -1;
+
+for (rnd = random_number(weights), i = 0; i < nproxies; i++)
+ {
+ sd = &proxies[i];
+ if (!sd->is_failed && sd->priority == pri)
+ if ((rnd -= sd->weight) < 0)
+ return i;
+ }
+
+log_write(0, LOG_MAIN|LOG_PANIC,
+ "%s unknown error (memory/cpu corruption?)", __FUNCTION__);
+return -1;
+}
+
+
+
/* Make a connection via a socks proxy
Arguments:
int
socks_sock_connect(host_item * host, int host_af, int port, uschar * interface,
transport_instance * tb, int timeout)
-
{
smtp_transport_options_block * ob =
(smtp_transport_options_block *)tb->options_block;
time_t tmo;
const uschar * state;
uschar buf[24];
+socks_opts proxies[32]; /* max #proxies handled */
+unsigned nproxies;
+socks_opts * sob = NULL;
+unsigned size;
+blob early_data;
if (!timeout) timeout = 24*60*60; /* use 1 day for "indefinite" */
tmo = time(NULL) + timeout;
return -1;
}
-/* Loop over proxy list, trying in order until one works */
-while ((proxy_spec = string_nextinlist(&proxy_list, &sep, NULL, 0)))
+/* Read proxy list */
+
+for (nproxies = 0;
+ nproxies < nelem(proxies)
+ && (proxy_spec = string_nextinlist(&proxy_list, &sep, NULL, 0));
+ nproxies++)
{
- const uschar * proxy_host;
int subsep = -' ';
- host_item proxy;
- int proxy_af;
- union sockaddr_46 sin;
- unsigned size;
- socks_opts sob;
const uschar * option;
- if (!(proxy_host = string_nextinlist(&proxy_spec, &subsep, NULL, 0)))
+ socks_option_defaults(sob = &proxies[nproxies]);
+
+ if (!(sob->proxy_host = string_nextinlist(&proxy_spec, &subsep, NULL, 0)))
{
/* paniclog config error */
return -1;
}
/*XXX consider global options eg. "hide socks_password = wibble" on the tpt */
- socks_option_defaults(&sob);
-
/* extract any further per-proxy options */
while ((option = string_nextinlist(&proxy_spec, &subsep, NULL, 0)))
- socks_option(&sob, option);
+ socks_option(sob, option);
+ }
+if (!sob) return -1;
+
+/* Set up the socks protocol method-selection message,
+for sending on connection */
+
+state = US"method select";
+buf[0] = 5; buf[1] = 1; buf[2] = sob->auth_type;
+early_data.data = buf;
+early_data.len = 3;
+
+/* Try proxies until a connection succeeds */
+
+for(;;)
+ {
+ int idx;
+ host_item proxy;
+ smtp_connect_args sc = {.sock = -1};
+
+ if ((idx = socks_get_proxy(proxies, nproxies)) < 0)
+ {
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" no proxies left\n");
+ errno = EBUSY;
+ return -1;
+ }
+ sob = &proxies[idx];
/* bodge up a host struct for the proxy */
- proxy.address = proxy_host;
- proxy_af = Ustrchr(proxy_host, ':') ? AF_INET6 : AF_INET;
-
- if ((fd = smtp_sock_connect(&proxy, proxy_af, sob.port,
- interface, tb, sob.timeout)) < 0)
- continue;
-
- /* Do the socks protocol stuff */
- /* Send method-selection */
- state = US"method select";
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" SOCKS>> 05 01 %02x\n", sob.auth_type);
- buf[0] = 5; buf[1] = 1; buf[2] = sob.auth_type;
- if (send(fd, buf, 3, 0) < 0)
- goto snd_err;
-
- /* expect method response */
- if ( !fd_ready(fd, tmo-time(NULL))
- || read(fd, buf, 2) != 2
- )
- goto rcv_err;
- HDEBUG(D_transport|D_acl|D_v)
- debug_printf(" SOCKS<< %02x %02x\n", buf[0], buf[1]);
- if ( buf[0] != 5
- || socks_auth(fd, buf[1], &sob, tmo) != OK
- )
- goto proxy_err;
+ proxy.address = proxy.name = sob->proxy_host;
+ proxy.port = sob->port;
+
+ sc.tblock = tb;
+ sc.ob = ob;
+ sc.host = &proxy;
+ sc.host_af = Ustrchr(sob->proxy_host, ':') ? AF_INET6 : AF_INET;
+ sc.interface = interface;
+
+ /*XXX we trust that the method-select command is idempotent */
+ if ((fd = smtp_sock_connect(&sc, sob->timeout, &early_data)) >= 0)
+ {
+ proxy_local_address = string_copy(proxy.address);
+ proxy_local_port = sob->port;
+ break;
+ }
+ log_write(0, LOG_MAIN, "%s: %s", __FUNCTION__, strerror(errno));
+ sob->is_failed = TRUE;
+ }
+
+/* Do the socks protocol stuff */
+
+HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SOCKS>> 05 01 %02x\n", sob->auth_type);
+
+/* expect method response */
+
+#ifdef TCP_QUICKACK
+(void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
+
+if ( !fd_ready(fd, tmo)
+ || read(fd, buf, 2) != 2
+ )
+ goto rcv_err;
+HDEBUG(D_transport|D_acl|D_v)
+ debug_printf_indent(" SOCKS<< %02x %02x\n", buf[0], buf[1]);
+if ( buf[0] != 5
+ || socks_auth(fd, buf[1], sob, tmo) != OK
+ )
+ goto proxy_err;
+
+ {
+ union sockaddr_46 sin;
(void) ip_addr(&sin, host_af, host->address, port);
/* send connect (ipver, ipaddr, port) */
+
buf[0] = 5; buf[1] = 1; buf[2] = 0; buf[3] = host_af == AF_INET6 ? 4 : 1;
-#if HAVE_IPV6
+ #if HAVE_IPV6
if (host_af == AF_INET6)
{
memcpy(buf+4, &sin.v6.sin6_addr, sizeof(sin.v6.sin6_addr));
size = 4+sizeof(sin.v6.sin6_addr)+sizeof(sin.v6.sin6_port);
}
else
-#endif
+ #endif
{
memcpy(buf+4, &sin.v4.sin_addr.s_addr, sizeof(sin.v4.sin_addr.s_addr));
memcpy(buf+4+sizeof(sin.v4.sin_addr.s_addr),
&sin.v4.sin_port, sizeof(sin.v4.sin_port));
size = 4+sizeof(sin.v4.sin_addr.s_addr)+sizeof(sin.v4.sin_port);
}
+ }
- state = US"connect";
- HDEBUG(D_transport|D_acl|D_v)
- {
- int i;
- debug_printf(" SOCKS>>");
- for (i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
- debug_printf("\n");
- }
- if (send(fd, buf, size, 0) < 0)
- goto snd_err;
-
- /* expect conn-reply (success, local(ipver, addr, port))
- of same length as conn-request, or non-success fail code */
- if ( !fd_ready(fd, tmo-time(NULL))
- || (size = read(fd, buf, size)) < 2
- )
- goto rcv_err;
- HDEBUG(D_transport|D_acl|D_v)
- {
- int i;
- debug_printf(" SOCKS>>");
- for (i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
- debug_printf("\n");
- }
- if ( buf[0] != 5
- || buf[1] != 0
- )
- goto proxy_err;
+state = US"connect";
+HDEBUG(D_transport|D_acl|D_v)
+ {
+ debug_printf_indent(" SOCKS>>");
+ for (int i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
+ debug_printf("\n");
+ }
+if (send(fd, buf, size, 0) < 0)
+ goto snd_err;
- /*XXX log proxy outbound addr/port? */
- HDEBUG(D_transport|D_acl|D_v)
- debug_printf(" proxy farside local: [%s]:%d\n",
- host_ntoa(buf[3] == 4 ? AF_INET6 : AF_INET, buf+4, NULL, NULL),
- ntohs(*((uint16_t *)(buf + (buf[3] == 4 ? 20 : 8)))));
+/* expect conn-reply (success, local(ipver, addr, port))
+of same length as conn-request, or non-success fail code */
- return fd;
+if ( !fd_ready(fd, tmo)
+ || (size = read(fd, buf, size)) < 2
+ )
+ goto rcv_err;
+HDEBUG(D_transport|D_acl|D_v)
+ {
+ debug_printf_indent(" SOCKS>>");
+ for (int i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
+ debug_printf("\n");
}
+if ( buf[0] != 5
+ || buf[1] != 0
+ )
+ goto proxy_err;
-HDEBUG(D_transport|D_acl|D_v) debug_printf(" no proxies left\n");
-return -1;
+proxy_external_address = string_copy(
+ host_ntoa(buf[3] == 4 ? AF_INET6 : AF_INET, buf+4, NULL, NULL));
+proxy_external_port = ntohs(*((uint16_t *)(buf + (buf[3] == 4 ? 20 : 8))));
+proxy_session = TRUE;
+
+HDEBUG(D_transport|D_acl|D_v)
+ debug_printf_indent(" proxy farside: [%s]:%d\n", proxy_external_address, proxy_external_port);
+
+return fd;
snd_err:
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" proxy snd_err %s: %s\n", state, strerror(errno));
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" proxy snd_err %s: %s\n", state, strerror(errno));
return -1;
proxy_err:
struct socks_err * se =
buf[1] > nelem(socks_errs) ? NULL : socks_errs + buf[1];
HDEBUG(D_transport|D_acl|D_v)
- debug_printf(" proxy %s: %s\n", state, se ? se->reason : US"unknown error code received");
+ debug_printf_indent(" proxy %s: %s\n", state, se ? se->reason : US"unknown error code received");
errno = se ? se->errcode : EPROTO;
}
rcv_err:
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" proxy rcv_err %s: %s\n", state, strerror(errno));
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" proxy rcv_err %s: %s\n", state, strerror(errno));
if (!errno) errno = EPROTO;
else if (errno == ENOENT) errno = ECONNABORTED;
return -1;
git://git.exim.org / exim.git / blobdiff