raw sockets: ttl can be set or auto-detected

The IP TTL used when sending on raw sockets can be set using the
core.udp4_raw_ttl config variable.
By default it is auto-detected on startup (the same IP TTL as the
one for the first udp4 socket is used).

cfg_core.c

@@ -56,6 +56,8 @@
 #include "pt.h"
 #endif
 #include "msg_translator.h" /* fix_global_req_flags() */
+#include "globals.h"
+#include "sock_ut.h"
 #include "cfg/cfg.h"
 #include "cfg_core.h"
 
@@ -113,6 +115,7 @@ struct cfg_group_core default_core_cfg = {
 	0, /*!< udp_mtu_try_proto -> default disabled */
 	0, /**< udp4_raw (disabled by default) */
 	1500, /**< udp4_raw_mtu (1500 by default) */
+	-1,  /**< udp4_raw_ttl (auto detect by default) */
 	0,  /*!< force_rport */
 	L_DBG, /*!< memlog */
 	1 /*!< mem_summary -flags: 0 off, 1 shm/pkg_status, 2 shm/pkg_sums */
@@ -153,6 +156,24 @@ static int check_raw_sock_support(void* cfg_h, str* gname, str* name,
 
 
 
+static int  udp4_raw_ttl_fixup(void* cfg_h, str* gname, str* name, void** val)
+{
+	int v;
+	v = (int)(long)(*val);
+	if (v < 0) {
+		if (sendipv4)
+			v = sock_get_ttl(sendipv4->socket);
+	}
+	if (v < 0) {
+		/* some error => use a reasonable default */
+		v = 63;
+	}
+	*val = (void*)(long)v;
+	return 0;
+}
+
+
+
 cfg_def_t core_cfg_def[] = {
 	{"debug",		CFG_VAR_INT|CFG_ATOMIC,	0, 0, 0, 0,
 		"debug level"},
@@ -264,6 +285,9 @@ cfg_def_t core_cfg_def[] = {
 		"set the MTU used when using raw sockets for udp sending."
 		" This  value will be used when deciding whether or not to fragment"
 		" the packets."},
+	{"udp4_raw_ttl", CFG_VAR_INT | CFG_ATOMIC, -1, 255, udp4_raw_ttl_fixup, 0,
+		"set the IP TTL used when using raw sockets for udp sending."
+		" -1 will use the same value as for normal udp sockets."},
 	{"force_rport",     CFG_VAR_INT, 0, 1,  0, fix_global_req_flags,
 		"force rport for all the received messages" },
 	{"memlog",		CFG_VAR_INT|CFG_ATOMIC,	0, 0, 0, 0,

cfg_core.h

@@ -103,6 +103,7 @@ struct cfg_group_core {
 	int udp_mtu_try_proto; /*!< if packet> udp_mtu, try proto (e.g. TCP) */
 	int udp4_raw; /* use raw sockets for sending on udp ipv 4 */
 	int udp4_raw_mtu; /* mtu used when using udp raw socket */
+	int udp4_raw_ttl; /* ttl used when using udp raw sockets */
 	int force_rport; /*!< if set rport will always be forced*/
 	int memlog; /*!< log level for memory status/summary info */
 	int mem_summary; /*!< display memory status/summary info on exit */

main.c

@@ -188,6 +188,7 @@
 #include "basex.h" /* init */
 #include "pvapi_init.h" /* init */
 #include "pv_core.h" /* register core pvars */
+#include "sock_ut.h"
 
 #ifdef DEBUG_DMALLOC
 #include <dmalloc.h>
@@ -1266,6 +1267,13 @@ int main_loop()
 				default_core_cfg.udp4_raw = 1; /* enabled */
 				DBG("raw socket possible => turning it on\n");
 			}
+			if (default_core_cfg.udp4_raw_ttl < 0) {
+				/* auto-detect */
+				default_core_cfg.udp4_raw_ttl = sock_get_ttl(sendipv4->socket);
+				if (default_core_cfg.udp4_raw_ttl < 0)
+					/* error, use some default value */
+					default_core_cfg.udp4_raw_ttl = 63;
+			}
 		}
 #else
 		default_core.cfg.udp4_raw = 0;
@@ -1417,6 +1425,14 @@ int main_loop()
 					default_core_cfg.udp4_raw = 1; /* enabled */
 					DBG("raw socket possible => turning it on\n");
 				}
+				if (default_core_cfg.udp4_raw_ttl < 0) {
+					/* auto-detect */
+					default_core_cfg.udp4_raw_ttl =
+						sock_get_ttl(sendipv4->socket);
+					if (default_core_cfg.udp4_raw_ttl < 0)
+						/* error, use some default value */
+						default_core_cfg.udp4_raw_ttl = 63;
+				}
 			}
 		}
 #else

raw_sock.c

@@ -56,6 +56,8 @@
 #include <netinet/udp.h>
 
 #include "raw_sock.h"
+#include "cfg/cfg.h"
+#include "cfg_core.h"
 
 
 /** create and return a raw socket.
@@ -79,11 +81,8 @@ int raw_socket(int proto, struct ip_addr* ip, str* iface, int iphdr_incl)
 	char* ifname;
 
 	sock = socket(PF_INET, SOCK_RAW, proto);
-	if (sock==-1){
-		ERR("raw_socket: socket() failed: %s [%d]\n",
-				strerror(errno), errno);
+	if (sock==-1)
 		goto error;
-	}
 	/* set socket options */
 	if (iphdr_incl) {
 		t=1;
@@ -426,7 +425,7 @@ inline static int mk_ip_hdr(struct ip* iph, struct in_addr* from,
 	iph->ip_len = htons(payload_len);
 	iph->ip_id = 0;
 	iph->ip_off = 0; /* frag.: first 3 bits=flags=0, last 13 bits=offset */
-	iph->ip_ttl = 63; /* FIXME: use some configured value */
+	iph->ip_ttl = cfg_get(core, core_cfg, udp4_raw_ttl);
 	iph->ip_p = proto;
 	iph->ip_sum = 0;
 	iph->ip_src = *from;

sock_ut.c

@@ -0,0 +1,71 @@
+/* 
+ * $Id$
+ * 
+ * Copyright (C) 2010 iptelorg GmbH
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/** various socket related functions.
+ * @file sock_ut.c
+ * @ingroup: core 
+ */
+/*
+ * History:
+ * --------
+ *  2010-08-09  initial version (andrei)
+*/
+
+#include "sock_ut.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+
+/** get the IP TTL.
+ * @return ttl on success, < 0 on error
+ */
+int sock_get_ttl(int sock)
+{
+	int ioptval;
+	unsigned int ioptvallen;
+
+	ioptvallen=sizeof(ioptval);
+	if (getsockopt( sock, IPPROTO_IP, IP_TTL, (void*) &ioptval,
+		    &ioptvallen) == -1 )
+	{
+		return -1;
+	}
+	return ioptval;
+}
+
+
+
+/** set the IP TTL on a socket.
+ * @return ttl on success, < 0 on error
+ */
+int sock_set_ttl(int sock, int ttl)
+{
+	int ioptval;
+
+	if (setsockopt( sock, IPPROTO_IP, IP_TTL, (void*) &ioptval,
+					sizeof(ioptval)) == -1 )
+		return -1;
+	return ioptval;
+}
+
+/* vi: set ts=4 sw=4 tw=79:ai:cindent: */

sock_ut.h

@@ -0,0 +1,39 @@
+/* 
+ * $Id$
+ * 
+ * Copyright (C) 2010 iptelorg GmbH
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/** various socket related functions.
+ * @file sock_ut.h
+ * @ingroup: core 
+ */
+/*
+ * History:
+ * --------
+ *  2010-08-09  initial version (andrei)
+*/
+
+#ifndef __sock_ut_h
+#define __sock_ut_h
+
+
+
+int sock_get_ttl(int sock);
+int sock_set_ttl(int sock, int ttl);
+
+
+#endif /*__sock_ut_h*/
+
+/* vi: set ts=4 sw=4 tw=79:ai:cindent: */