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/*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* $Id: ce0147da326582973dbbc5986b7dfabb8e037822 $
* @file udpfromto.c
* @brief Like recvfrom, but also stores the destination IP address. Useful on multihomed hosts.
*
* @copyright 2007 Alan DeKok <aland@deployingradius.com>
* @copyright 2002 Miquel van Smoorenburg
*/
RCSID("$Id: ce0147da326582973dbbc5986b7dfabb8e037822 $")
#include <freeradius-devel/udpfromto.h>
#ifdef WITH_UDPFROMTO
#ifdef HAVE_SYS_UIO_H
# include <sys/uio.h>
#endif
#include <fcntl.h>
/*
* More portability idiocy
* Mac OSX Lion doesn't define SOL_IP. But IPPROTO_IP works.
*/
#ifndef SOL_IP
# define SOL_IP IPPROTO_IP
#endif
/*
* glibc 2.4 and uClibc 0.9.29 introduce IPV6_RECVPKTINFO etc. and
* change IPV6_PKTINFO This is only supported in Linux kernel >=
* 2.6.14
*
* This is only an approximation because the kernel version that libc
* was compiled against could be older or newer than the one being
* run. But this should not be a problem -- we just keep using the
* old kernel interface.
*/
#ifdef __linux__
# ifdef IPV6_RECVPKTINFO
# include <linux/version.h>
# if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,14)
# ifdef IPV6_2292PKTINFO
# undef IPV6_RECVPKTINFO
# undef IPV6_PKTINFO
# define IPV6_RECVPKTINFO IPV6_2292PKTINFO
# define IPV6_PKTINFO IPV6_2292PKTINFO
# endif
# endif
/* Fall back to the legacy socket option if IPV6_RECVPKTINFO isn't defined */
# elif defined(IPV6_2292PKTINFO)
# define IPV6_RECVPKTINFO IPV6_2292PKTINFO
# endif
#else
/*
* For everything that's not Linux we assume RFC 3542 compliance
* - setsockopt() takes IPV6_RECVPKTINFO
* - cmsg_type is IPV6_PKTINFO (in sendmsg, recvmsg)
*
* If we don't have IPV6_RECVPKTINFO defined but do have IPV6_PKTINFO
* defined, chances are the API is RFC2292 compliant and we need to use
* IPV6_PKTINFO for both.
*/
# if !defined(IPV6_RECVPKTINFO) && defined(IPV6_PKTINFO)
# define IPV6_RECVPKTINFO IPV6_PKTINFO
/*
* Ensure IPV6_RECVPKTINFO is not defined somehow if we have we
* don't have IPV6_PKTINFO.
*/
# elif !defined(IPV6_PKTINFO)
# undef IPV6_RECVPKTINFO
# endif
#endif
int udpfromto_init(int s)
{
int proto, flag = 0, opt = 1;
struct sockaddr_storage si;
socklen_t si_len = sizeof(si);
errno = ENOSYS;
/*
* Clang analyzer doesn't see that getsockname initialises
* the memory passed to it.
*/
#ifdef __clang_analyzer__
memset(&si, 0, sizeof(si));
#endif
if (getsockname(s, (struct sockaddr *) &si, &si_len) < 0) {
return -1;
}
if (si.ss_family == AF_INET) {
#ifdef HAVE_IP_PKTINFO
/*
* Linux
*/
proto = SOL_IP;
flag = IP_PKTINFO;
#else
# ifdef IP_RECVDSTADDR
/*
* Set the IP_RECVDSTADDR option (BSD). Note:
* IP_RECVDSTADDR == IP_SENDSRCADDR
*/
proto = IPPROTO_IP;
flag = IP_RECVDSTADDR;
# else
return -1;
# endif
#endif
#if defined(AF_INET6) && defined(IPV6_PKTINFO)
} else if (si.ss_family == AF_INET6) {
/*
* This should actually be standard IPv6
*/
proto = IPPROTO_IPV6;
/*
* Work around Linux-specific hackery.
*/
flag = IPV6_RECVPKTINFO;
} else {
#endif
/*
* Unknown AF. Return an error if possible.
*/
# ifdef EPROTONOSUPPORT
errno = EPROTONOSUPPORT;
# endif
return -1;
}
return setsockopt(s, proto, flag, &opt, sizeof(opt));
}
int recvfromto(int s, void *buf, size_t len, int flags,
struct sockaddr *from, socklen_t *fromlen,
struct sockaddr *to, socklen_t *tolen)
{
struct msghdr msgh;
struct cmsghdr *cmsg;
struct iovec iov;
char cbuf[256];
int err;
struct sockaddr_storage si;
socklen_t si_len = sizeof(si);
#if !defined(IP_PKTINFO) && !defined(IP_RECVDSTADDR) && !defined(IPV6_PKTINFO)
/*
* If the recvmsg() flags aren't defined, fall back to
* using recvfrom().
*/
to = NULL:
#endif
/*
* Catch the case where the caller passes invalid arguments.
*/
if (!to || !tolen) return recvfrom(s, buf, len, flags, from, fromlen);
/*
* Clang analyzer doesn't see that getsockname initialises
* the memory passed to it.
*/
#ifdef __clang_analyzer__
memset(&si, 0, sizeof(si));
#endif
/*
* recvmsg doesn't provide sin_port so we have to
* retrieve it using getsockname().
*/
if (getsockname(s, (struct sockaddr *)&si, &si_len) < 0) {
return -1;
}
/*
* Initialize the 'to' address. It may be INADDR_ANY here,
* with a more specific address given by recvmsg(), below.
*/
if (si.ss_family == AF_INET) {
#if !defined(IP_PKTINFO) && !defined(IP_RECVDSTADDR)
return recvfrom(s, buf, len, flags, from, fromlen);
#else
struct sockaddr_in *dst = (struct sockaddr_in *) to;
struct sockaddr_in *src = (struct sockaddr_in *) &si;
if (*tolen < sizeof(*dst)) {
errno = EINVAL;
return -1;
}
*tolen = sizeof(*dst);
*dst = *src;
#endif
}
#ifdef AF_INET6
else if (si.ss_family == AF_INET6) {
#if !defined(IPV6_PKTINFO)
return recvfrom(s, buf, len, flags, from, fromlen);
#else
struct sockaddr_in6 *dst = (struct sockaddr_in6 *) to;
struct sockaddr_in6 *src = (struct sockaddr_in6 *) &si;
if (*tolen < sizeof(*dst)) {
errno = EINVAL;
return -1;
}
*tolen = sizeof(*dst);
*dst = *src;
#endif
}
#endif
/*
* Unknown address family.
*/
else {
errno = EINVAL;
return -1;
}
/* Set up iov and msgh structures. */
memset(&cbuf, 0, sizeof(cbuf));
memset(&msgh, 0, sizeof(struct msghdr));
iov.iov_base = buf;
iov.iov_len = len;
msgh.msg_control = cbuf;
msgh.msg_controllen = sizeof(cbuf);
msgh.msg_name = from;
msgh.msg_namelen = fromlen ? *fromlen : 0;
msgh.msg_iov = &iov;
msgh.msg_iovlen = 1;
msgh.msg_flags = 0;
/* Receive one packet. */
if ((err = recvmsg(s, &msgh, flags)) < 0) {
return err;
}
if (fromlen) *fromlen = msgh.msg_namelen;
/* Process auxiliary received data in msgh */
for (cmsg = CMSG_FIRSTHDR(&msgh);
cmsg != NULL;
cmsg = CMSG_NXTHDR(&msgh,cmsg)) {
#ifdef IP_PKTINFO
if ((cmsg->cmsg_level == SOL_IP) &&
(cmsg->cmsg_type == IP_PKTINFO)) {
struct in_pktinfo *i =
(struct in_pktinfo *) CMSG_DATA(cmsg);
((struct sockaddr_in *)to)->sin_addr = i->ipi_addr;
*tolen = sizeof(struct sockaddr_in);
break;
}
#endif
#ifdef IP_RECVDSTADDR
if ((cmsg->cmsg_level == IPPROTO_IP) &&
(cmsg->cmsg_type == IP_RECVDSTADDR)) {
struct in_addr *i = (struct in_addr *) CMSG_DATA(cmsg);
((struct sockaddr_in *)to)->sin_addr = *i;
*tolen = sizeof(struct sockaddr_in);
break;
}
#endif
#ifdef IPV6_PKTINFO
if ((cmsg->cmsg_level == IPPROTO_IPV6) &&
(cmsg->cmsg_type == IPV6_PKTINFO)) {
struct in6_pktinfo *i =
(struct in6_pktinfo *) CMSG_DATA(cmsg);
((struct sockaddr_in6 *)to)->sin6_addr = i->ipi6_addr;
*tolen = sizeof(struct sockaddr_in6);
break;
}
#endif
}
return err;
}
int sendfromto(int s, void *buf, size_t len, int flags,
struct sockaddr *from, socklen_t fromlen,
struct sockaddr *to, socklen_t tolen)
{
struct msghdr msgh;
struct iovec iov;
char cbuf[256];
/*
* Unknown address family, die.
*/
if (from && (from->sa_family != AF_INET) && (from->sa_family != AF_INET6)) {
errno = EINVAL;
return -1;
}
#ifdef __FreeBSD__
/*
* FreeBSD is extra pedantic about the use of IP_SENDSRCADDR,
* and sendmsg will fail with EINVAL if IP_SENDSRCADDR is used
* with a socket which is bound to something other than
* INADDR_ANY
*/
struct sockaddr bound;
socklen_t bound_len = sizeof(bound);
if (getsockname(s, &bound, &bound_len) < 0) {
return -1;
}
switch (bound.sa_family) {
case AF_INET:
if (((struct sockaddr_in *) &bound)->sin_addr.s_addr != INADDR_ANY) {
from = NULL;
}
break;
case AF_INET6:
if (!IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *) &bound)->sin6_addr)) {
from = NULL;
}
break;
}
#endif /* !__FreeBSD__ */
/*
* If the sendmsg() flags aren't defined, fall back to
* using sendto(). These flags are defined on FreeBSD,
* but laying it out this way simplifies the look of the
* code.
*/
# if !defined(IP_PKTINFO) && !defined(IP_SENDSRCADDR)
if (from && from->sa_family == AF_INET) {
from = NULL;
}
# endif
# if !defined(IPV6_PKTINFO)
if (from && from->sa_family == AF_INET6) {
from = NULL;
}
# endif
/*
* No "from", just use regular sendto.
*/
if (!from || (fromlen == 0)) {
return sendto(s, buf, len, flags, to, tolen);
}
/* Set up control buffer iov and msgh structures. */
memset(&cbuf, 0, sizeof(cbuf));
memset(&msgh, 0, sizeof(msgh));
memset(&iov, 0, sizeof(iov));
iov.iov_base = buf;
iov.iov_len = len;
msgh.msg_iov = &iov;
msgh.msg_iovlen = 1;
msgh.msg_name = to;
msgh.msg_namelen = tolen;
# if defined(IP_PKTINFO) || defined(IP_SENDSRCADDR)
if (from->sa_family == AF_INET) {
struct sockaddr_in *s4 = (struct sockaddr_in *) from;
# ifdef IP_PKTINFO
struct cmsghdr *cmsg;
struct in_pktinfo *pkt;
msgh.msg_control = cbuf;
msgh.msg_controllen = CMSG_SPACE(sizeof(*pkt));
cmsg = CMSG_FIRSTHDR(&msgh);
cmsg->cmsg_level = SOL_IP;
cmsg->cmsg_type = IP_PKTINFO;
cmsg->cmsg_len = CMSG_LEN(sizeof(*pkt));
pkt = (struct in_pktinfo *) CMSG_DATA(cmsg);
memset(pkt, 0, sizeof(*pkt));
pkt->ipi_spec_dst = s4->sin_addr;
# endif
# ifdef IP_SENDSRCADDR
struct cmsghdr *cmsg;
struct in_addr *in;
msgh.msg_control = cbuf;
msgh.msg_controllen = CMSG_SPACE(sizeof(*in));
cmsg = CMSG_FIRSTHDR(&msgh);
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_SENDSRCADDR;
cmsg->cmsg_len = CMSG_LEN(sizeof(*in));
in = (struct in_addr *) CMSG_DATA(cmsg);
*in = s4->sin_addr;
# endif
}
#endif
# if defined(IPV6_PKTINFO)
if (from->sa_family == AF_INET6) {
struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) from;
struct cmsghdr *cmsg;
struct in6_pktinfo *pkt;
msgh.msg_control = cbuf;
msgh.msg_controllen = CMSG_SPACE(sizeof(*pkt));
cmsg = CMSG_FIRSTHDR(&msgh);
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
cmsg->cmsg_len = CMSG_LEN(sizeof(*pkt));
pkt = (struct in6_pktinfo *) CMSG_DATA(cmsg);
memset(pkt, 0, sizeof(*pkt));
pkt->ipi6_addr = s6->sin6_addr;
}
# endif /* IPV6_PKTINFO */
return sendmsg(s, &msgh, flags);
}
#ifdef TESTING
/*
* Small test program to test recvfromto/sendfromto
*
* use a virtual IP address as first argument to test
*
* reply packet should originate from virtual IP and not
* from the default interface the alias is bound to
*/
# include <sys/wait.h>
# define DEF_PORT 20000 /* default port to listen on */
# define DESTIP "127.0.0.1" /* send packet to localhost per default */
# define TESTSTRING "foo" /* what to send */
# define TESTLEN 4 /* 4 bytes */
int main(int argc, char **argv)
{
struct sockaddr_in from, to, in;
char buf[TESTLEN];
char *destip = DESTIP;
uint16_t port = DEF_PORT;
int n, server_socket, client_socket, fl, tl, pid;
if (argc > 1) destip = argv[1];
if (argc > 2) port = atoi(argv[2]);
in.sin_family = AF_INET;
in.sin_addr.s_addr = INADDR_ANY;
in.sin_port = htons(port);
fl = tl = sizeof(struct sockaddr_in);
memset(&from, 0, sizeof(from));
memset(&to, 0, sizeof(to));
switch (pid = fork()) {
case -1:
perror("fork");
return 0;
case 0:
/* child */
usleep(100000);
goto client;
}
/* parent: server */
server_socket = socket(PF_INET, SOCK_DGRAM, 0);
if (udpfromto_init(server_socket) != 0) {
perror("udpfromto_init\n");
waitpid(pid, NULL, WNOHANG);
return 0;
}
if (bind(server_socket, (struct sockaddr *)&in, sizeof(in)) < 0) {
perror("server: bind");
waitpid(pid, NULL, WNOHANG);
return 0;
}
printf("server: waiting for packets on INADDR_ANY:%d\n", port);
if ((n = recvfromto(server_socket, buf, sizeof(buf), 0,
(struct sockaddr *)&from, &fl,
(struct sockaddr *)&to, &tl)) < 0) {
perror("server: recvfromto");
waitpid(pid, NULL, WNOHANG);
return 0;
}
printf("server: received a packet of %d bytes [%s] ", n, buf);
printf("(src ip:port %s:%d ",
inet_ntoa(from.sin_addr), ntohs(from.sin_port));
printf(" dst ip:port %s:%d)\n",
inet_ntoa(to.sin_addr), ntohs(to.sin_port));
printf("server: replying from address packet was received on to source address\n");
if ((n = sendfromto(server_socket, buf, n, 0,
(struct sockaddr *)&to, tl,
(struct sockaddr *)&from, fl)) < 0) {
perror("server: sendfromto");
}
waitpid(pid, NULL, 0);
return 0;
client:
close(server_socket);
client_socket = socket(PF_INET, SOCK_DGRAM, 0);
if (udpfromto_init(client_socket) != 0) {
perror("udpfromto_init");
fr_exit_now(0);
}
/* bind client on different port */
in.sin_port = htons(port+1);
if (bind(client_socket, (struct sockaddr *)&in, sizeof(in)) < 0) {
perror("client: bind");
fr_exit_now(0);
}
in.sin_port = htons(port);
in.sin_addr.s_addr = inet_addr(destip);
printf("client: sending packet to %s:%d\n", destip, port);
if (sendto(client_socket, TESTSTRING, TESTLEN, 0,
(struct sockaddr *)&in, sizeof(in)) < 0) {
perror("client: sendto");
fr_exit_now(0);
}
printf("client: waiting for reply from server on INADDR_ANY:%d\n", port+1);
if ((n = recvfromto(client_socket, buf, sizeof(buf), 0,
(struct sockaddr *)&from, &fl,
(struct sockaddr *)&to, &tl)) < 0) {
perror("client: recvfromto");
fr_exit_now(0);
}
printf("client: received a packet of %d bytes [%s] ", n, buf);
printf("(src ip:port %s:%d",
inet_ntoa(from.sin_addr), ntohs(from.sin_port));
printf(" dst ip:port %s:%d)\n",
inet_ntoa(to.sin_addr), ntohs(to.sin_port));
fr_exit_now(0);
}
#endif /* TESTING */
#endif /* WITH_UDPFROMTO */
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