*
* Copyright (C) 2007 Denys Vlasenko
*
- * Licensed under GPL version 2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
-
#include "libbb.h"
+#if defined(IPV6_PKTINFO) && !defined(IPV6_RECVPKTINFO)
+# define IPV6_RECVPKTINFO IPV6_PKTINFO
+#endif
+
/*
* This asks kernel to let us know dst addr/port of incoming packets
* We don't check for errors here. Not supported == won't be used
*/
-void
-socket_want_pktinfo(int fd)
+void FAST_FUNC
+socket_want_pktinfo(int fd UNUSED_PARAM)
{
#ifdef IP_PKTINFO
- setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int));
+ setsockopt_1(fd, IPPROTO_IP, IP_PKTINFO);
#endif
-#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
- setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &const_int_1, sizeof(int));
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_RECVPKTINFO)
+ setsockopt_1(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO);
#endif
}
-#ifdef UNUSED
-ssize_t
+ssize_t FAST_FUNC
send_to_from(int fd, void *buf, size_t len, int flags,
- const struct sockaddr *from, const struct sockaddr *to,
+ const struct sockaddr *to,
+ const struct sockaddr *from,
socklen_t tolen)
{
#ifndef IP_PKTINFO
+ (void)from; /* suppress "unused from" warning */
return sendto(fd, buf, len, flags, to, tolen);
#else
struct iovec iov[1];
struct msghdr msg;
- char cbuf[sizeof(struct in_pktinfo)
-#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
- | sizeof(struct in6_pktinfo) /* (a|b) is poor man's max(a,b) */
-#endif
- ];
+ union {
+ char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
+# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
+ char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+# endif
+ } u;
struct cmsghdr* cmsgptr;
if (from->sa_family != AF_INET
-#if ENABLE_FEATURE_IPV6
+# if ENABLE_FEATURE_IPV6
&& from->sa_family != AF_INET6
-#endif
+# endif
) {
/* ANY local address */
return sendto(fd, buf, len, flags, to, tolen);
iov[0].iov_base = buf;
iov[0].iov_len = len;
- memset(cbuf, 0, sizeof(cbuf));
+ memset(&u, 0, sizeof(u));
memset(&msg, 0, sizeof(msg));
msg.msg_name = (void *)(struct sockaddr *)to; /* or compiler will annoy us */
msg.msg_namelen = tolen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
- msg.msg_control = cbuf;
- msg.msg_controllen = sizeof(cbuf);
+ msg.msg_control = &u;
+ msg.msg_controllen = sizeof(u);
msg.msg_flags = flags;
cmsgptr = CMSG_FIRSTHDR(&msg);
- if (to->sa_family == AF_INET && from->sa_family == AF_INET) {
+ /*
+ * Users report that to->sa_family can be AF_INET6 too,
+ * if "to" was acquired by recv_from_to(). IOW: recv_from_to()
+ * was seen showing IPv6 "from" even when the destination
+ * of received packet (our local address) was IPv4.
+ */
+ if (/* to->sa_family == AF_INET && */ from->sa_family == AF_INET) {
struct in_pktinfo *pktptr;
cmsgptr->cmsg_level = IPPROTO_IP;
cmsgptr->cmsg_type = IP_PKTINFO;
cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
pktptr = (struct in_pktinfo *)(CMSG_DATA(cmsgptr));
- /* pktptr->ipi_ifindex = 0; -- already done by memset(cbuf...) */
+ /*pktptr->ipi_ifindex = 0; -- already done by memset(u...) */
+ /* In general, CMSG_DATA() can be unaligned, but in this case
+ * we know for sure it is sufficiently aligned:
+ * CMSG_FIRSTHDR simply returns &u above,
+ * and CMSG_DATA returns &u + size_t + int + int.
+ * Thus direct assignment is ok:
+ */
pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr;
}
-#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
- else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) {
+# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
+ else if (/* to->sa_family == AF_INET6 && */ from->sa_family == AF_INET6) {
struct in6_pktinfo *pktptr;
cmsgptr->cmsg_level = IPPROTO_IPV6;
cmsgptr->cmsg_type = IPV6_PKTINFO;
cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr));
- /* pktptr->ipi6_ifindex = 0; -- already done by memset(cbuf...) */
+ /* pktptr->ipi6_ifindex = 0; -- already done by memset(u...) */
pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr;
}
-#endif
+# endif
+ msg.msg_controllen = cmsgptr->cmsg_len;
+
return sendmsg(fd, &msg, flags);
#endif
}
-#endif /* UNUSED */
/* NB: this will never set port# in 'to'!
* _Only_ IP/IPv6 address part of 'to' is _maybe_ modified.
* Typical usage is to preinit 'to' with "default" value
* before calling recv_from_to(). */
-ssize_t
+ssize_t FAST_FUNC
recv_from_to(int fd, void *buf, size_t len, int flags,
struct sockaddr *from, struct sockaddr *to,
socklen_t sa_size)
{
#ifndef IP_PKTINFO
+ (void)to; /* suppress "unused to" warning */
return recvfrom(fd, buf, len, flags, from, &sa_size);
#else
/* man recvmsg and man cmsg is needed to make sense of code below */
struct iovec iov[1];
union {
char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
+# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+# endif
} u;
struct cmsghdr *cmsgptr;
struct msghdr msg;
- socklen_t recv_length;
+ ssize_t recv_length;
iov[0].iov_base = buf;
iov[0].iov_len = len;
if (recv_length < 0)
return recv_length;
+# define to4 ((struct sockaddr_in*)to)
+# define to6 ((struct sockaddr_in6*)to)
/* Here we try to retrieve destination IP and memorize it */
for (cmsgptr = CMSG_FIRSTHDR(&msg);
cmsgptr != NULL;
if (cmsgptr->cmsg_level == IPPROTO_IP
&& cmsgptr->cmsg_type == IP_PKTINFO
) {
-#define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )
+ const int IPI_ADDR_OFF = offsetof(struct in_pktinfo, ipi_addr);
to->sa_family = AF_INET;
- ((struct sockaddr_in*)to)->sin_addr = pktinfo(cmsgptr)->ipi_addr;
- /* ((struct sockaddr_in*)to)->sin_port = 123; */
-#undef pktinfo
+ /*# define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )*/
+ /*to4->sin_addr = pktinfo(cmsgptr)->ipi_addr; - may be unaligned */
+ memcpy(&to4->sin_addr, (char*)(CMSG_DATA(cmsgptr)) + IPI_ADDR_OFF, sizeof(to4->sin_addr));
+ /*to4->sin_port = 123; - this data is not supplied by kernel */
break;
}
-#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
+# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
if (cmsgptr->cmsg_level == IPPROTO_IPV6
&& cmsgptr->cmsg_type == IPV6_PKTINFO
) {
-#define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
+ const int IPI6_ADDR_OFF = offsetof(struct in6_pktinfo, ipi6_addr);
to->sa_family = AF_INET6;
- ((struct sockaddr_in6*)to)->sin6_addr = pktinfo(cmsgptr)->ipi6_addr;
- /* ((struct sockaddr_in6*)to)->sin6_port = 123; */
-#undef pktinfo
+ /*# define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )*/
+ /*to6->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; - may be unaligned */
+ memcpy(&to6->sin6_addr, (char*)(CMSG_DATA(cmsgptr)) + IPI6_ADDR_OFF, sizeof(to6->sin6_addr));
+ /*to6->sin6_port = 123; */
break;
}
-#endif
+# endif
}
return recv_length;
#endif
projects / oweals / busybox.git / blobdiff