2 * This library is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU Lesser General Public
4 * License as published by the Free Software Foundation; either
5 * version 2.1 of the License, or (at your option) any later version.
7 * This library is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * Lesser General Public License for more details.
12 * You should have received a copy of the GNU Lesser General Public
13 * License along with this library; if not, write to the Free Software
14 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
16 * Helper functions to get/set addresses of UDP packets
17 * based on recvfromto by Miquel van Smoorenburg
19 * recvfromto Like recvfrom, but also stores the destination
20 * IP address. Useful on multihomed hosts.
22 * Should work on Linux and BSD.
24 * Copyright (C) 2002 Miquel van Smoorenburg.
26 * This program is free software; you can redistribute it and/or
27 * modify it under the terms of the GNU Lesser General Public
28 * License as published by the Free Software Foundation; either
29 * version 2 of the License, or (at your option) any later version.
31 * sendfromto added 18/08/2003, Jan Berkel <jan@sitadelle.com>
32 * Works on Linux and FreeBSD (5.x)
37 #include <freeradius-devel/ident.h>
40 #include <freeradius-devel/udpfromto.h>
51 int udpfromto_init(int s)
53 int err = -1, opt = 1;
55 #ifdef HAVE_IP_PKTINFO
56 /* Set the IP_PKTINFO option (Linux). */
57 err = setsockopt(s, SOL_IP, IP_PKTINFO, &opt, sizeof(opt));
60 #ifdef HAVE_IP_RECVDSTADDR
62 * Set the IP_RECVDSTADDR option (BSD).
63 * Note: IP_RECVDSTADDR == IP_SENDSRCADDR
65 err = setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, &opt, sizeof(opt));
70 int recvfromto(int s, void *buf, size_t len, int flags,
71 struct sockaddr *from, socklen_t *fromlen,
72 struct sockaddr *to, socklen_t *tolen)
74 #if defined(HAVE_IP_PKTINFO) || defined(HAVE_IP_RECVDSTADDR)
82 * If from or to are set, they must be big enough
83 * to store a struct sockaddr_in.
85 if ((from && (!fromlen || *fromlen < sizeof(struct sockaddr_in))) ||
86 (to && (!tolen || *tolen < sizeof(struct sockaddr_in)))) {
92 * IP_PKTINFO / IP_RECVDSTADDR don't provide sin_port so we have to
93 * retrieve it using getsockname().
96 struct sockaddr_in si;
97 socklen_t l = sizeof(si);
99 ((struct sockaddr_in *)to)->sin_family = AF_INET;
100 ((struct sockaddr_in *)to)->sin_port = 0;
102 if (getsockname(s, (struct sockaddr *)&si, &l) == 0) {
103 ((struct sockaddr_in *)to)->sin_port = si.sin_port;
104 ((struct sockaddr_in *)to)->sin_addr = si.sin_addr;
106 if (tolen) *tolen = sizeof(struct sockaddr_in);
109 /* Set up iov and msgh structures. */
110 memset(&msgh, 0, sizeof(struct msghdr));
113 msgh.msg_control = cbuf;
114 msgh.msg_controllen = sizeof(cbuf);
115 msgh.msg_name = from;
116 msgh.msg_namelen = fromlen ? *fromlen : 0;
121 /* Receive one packet. */
122 if ((err = recvmsg(s, &msgh, flags)) < 0) {
125 if (fromlen) *fromlen = msgh.msg_namelen;
127 /* Process auxiliary received data in msgh */
128 for (cmsg = CMSG_FIRSTHDR(&msgh);
130 cmsg = CMSG_NXTHDR(&msgh,cmsg)) {
132 # ifdef HAVE_IP_PKTINFO
133 if (cmsg->cmsg_level == SOL_IP
134 && cmsg->cmsg_type == IP_PKTINFO) {
135 struct in_pktinfo *i =
136 (struct in_pktinfo *)CMSG_DATA(cmsg);
138 ((struct sockaddr_in *)to)->sin_addr =
140 if (tolen) *tolen = sizeof(struct sockaddr_in);
146 # ifdef HAVE_IP_RECVDSTADDR
147 if (cmsg->cmsg_level == IPPROTO_IP
148 && cmsg->cmsg_type == IP_RECVDSTADDR) {
149 struct in_addr *i = (struct in_addr *)CMSG_DATA(cmsg);
151 ((struct sockaddr_in *)to)->sin_addr = *i;
152 if (tolen) *tolen = sizeof(struct sockaddr_in);
160 /* fallback: call recvfrom */
161 return recvfrom(s, buf, len, flags, from, fromlen);
162 #endif /* defined(HAVE_IP_PKTINFO) || defined(HAVE_IP_RECVDSTADDR) */
165 int sendfromto(int s, void *buf, size_t len, int flags,
166 struct sockaddr *from, socklen_t fromlen,
167 struct sockaddr *to, socklen_t tolen)
169 #if defined(HAVE_IP_PKTINFO) || defined(HAVE_IP_SENDSRCADDR)
171 struct cmsghdr *cmsg;
173 # ifdef HAVE_IP_PKTINFO
174 char cmsgbuf[CMSG_SPACE(sizeof(struct in_pktinfo))];
175 struct in_pktinfo pktinfo, *pktinfo_ptr;
176 memset(&pktinfo, 0, sizeof(struct in_pktinfo));
178 struct sockaddr_in *s4;
180 # ifdef HAVE_IP_SENDSRCADDR
181 char cmsgbuf[CMSG_SPACE(sizeof(struct in_addr))];
184 s4 = (struct sockaddr_in *) from;
187 * Source is unset, empty, or unspecified,
188 * fall back to sendto().
190 if (!s4 || (fromlen == 0) || (s4->sin_family == AF_UNSPEC)) {
191 return sendto(s, buf, len, flags, to, tolen);
194 /* Set up iov and msgh structures. */
195 memset(&msgh, 0, sizeof(struct msghdr));
200 msgh.msg_control = cmsgbuf;
201 msgh.msg_controllen = sizeof(cmsgbuf);
203 msgh.msg_namelen = tolen;
205 cmsg = CMSG_FIRSTHDR(&msgh);
207 # ifdef HAVE_IP_PKTINFO
208 cmsg->cmsg_level = SOL_IP;
209 cmsg->cmsg_type = IP_PKTINFO;
210 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
211 pktinfo.ipi_spec_dst = ((struct sockaddr_in *)from)->sin_addr;
212 pktinfo_ptr = (struct in_pktinfo *)CMSG_DATA(cmsg);
213 memcpy(pktinfo_ptr, &pktinfo, sizeof(struct in_pktinfo));
215 # ifdef HAVE_IP_SENDSRCADDR
216 cmsg->cmsg_level = IPPROTO_IP;
217 cmsg->cmsg_type = IP_SENDSRCADDR;
218 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
219 memcpy((struct in_addr *)CMSG_DATA(cmsg),
220 &((struct sockaddr_in *)from)->sin_addr, sizeof(struct in_addr));
223 return sendmsg(s, &msgh, flags);
225 /* fallback: call sendto() */
226 return sendto(s, buf, len, flags, to, tolen);
227 #endif /* defined(HAVE_IP_PKTINFO) || defined (HAVE_IP_SENDSRCADDR) */
233 * Small test program to test recvfromto/sendfromto
235 * use a virtual IP address as first argument to test
237 * reply packet should originate from virtual IP and not
238 * from the default interface the alias is bound to
243 #include <arpa/inet.h>
244 #include <sys/types.h>
245 #include <sys/wait.h>
247 #define DEF_PORT 20000 /* default port to listen on */
248 #define DESTIP "127.0.0.1" /* send packet to localhost per default */
249 #define TESTSTRING "foo" /* what to send */
250 #define TESTLEN 4 /* 4 bytes */
252 int main(int argc, char **argv)
254 struct sockaddr_in from, to, in;
256 char *destip = DESTIP;
258 int n, server_socket, client_socket, fl, tl, pid;
260 if (argc > 1) destip = argv[1];
261 if (argc > 2) port = atoi(argv[2]);
263 in.sin_family = AF_INET;
264 in.sin_addr.s_addr = INADDR_ANY;
265 in.sin_port = htons(port);
266 fl = tl = sizeof(struct sockaddr_in);
267 memset(&from, 0, sizeof(from));
268 memset(&to, 0, sizeof(to));
270 switch(pid = fork()) {
281 server_socket = socket(PF_INET, SOCK_DGRAM, 0);
282 if (udpfromto_init(server_socket) != 0) {
283 perror("udpfromto_init\n");
284 waitpid(pid, NULL, WNOHANG);
288 if (bind(server_socket, (struct sockaddr *)&in, sizeof(in)) < 0) {
289 perror("server: bind");
290 waitpid(pid, NULL, WNOHANG);
294 printf("server: waiting for packets on INADDR_ANY:%d\n", port);
295 if ((n = recvfromto(server_socket, buf, sizeof(buf), 0,
296 (struct sockaddr *)&from, &fl,
297 (struct sockaddr *)&to, &tl)) < 0) {
298 perror("server: recvfromto");
299 waitpid(pid, NULL, WNOHANG);
303 printf("server: received a packet of %d bytes [%s] ", n, buf);
304 printf("(src ip:port %s:%d ",
305 inet_ntoa(from.sin_addr), ntohs(from.sin_port));
306 printf(" dst ip:port %s:%d)\n",
307 inet_ntoa(to.sin_addr), ntohs(to.sin_port));
309 printf("server: replying from address packet was received on to source address\n");
311 if ((n = sendfromto(server_socket, buf, n, 0,
312 (struct sockaddr *)&to, tl,
313 (struct sockaddr *)&from, fl)) < 0) {
314 perror("server: sendfromto");
317 waitpid(pid, NULL, 0);
321 close(server_socket);
322 client_socket = socket(PF_INET, SOCK_DGRAM, 0);
323 if (udpfromto_init(client_socket) != 0) {
324 perror("udpfromto_init");
327 /* bind client on different port */
328 in.sin_port = htons(port+1);
329 if (bind(client_socket, (struct sockaddr *)&in, sizeof(in)) < 0) {
330 perror("client: bind");
334 in.sin_port = htons(port);
335 in.sin_addr.s_addr = inet_addr(destip);
337 printf("client: sending packet to %s:%d\n", destip, port);
338 if (sendto(client_socket, TESTSTRING, TESTLEN, 0,
339 (struct sockaddr *)&in, sizeof(in)) < 0) {
340 perror("client: sendto");
344 printf("client: waiting for reply from server on INADDR_ANY:%d\n", port+1);
346 if ((n = recvfromto(client_socket, buf, sizeof(buf), 0,
347 (struct sockaddr *)&from, &fl,
348 (struct sockaddr *)&to, &tl)) < 0) {
349 perror("client: recvfromto");
353 printf("client: received a packet of %d bytes [%s] ", n, buf);
354 printf("(src ip:port %s:%d",
355 inet_ntoa(from.sin_addr), ntohs(from.sin_port));
356 printf(" dst ip:port %s:%d)\n",
357 inet_ntoa(to.sin_addr), ntohs(to.sin_port));
363 #endif /* WITH_UDPFROMTO */