diff options
| -rw-r--r-- | libbb/udp_io.c | 53 |
1 files changed, 32 insertions, 21 deletions
diff --git a/libbb/udp_io.c b/libbb/udp_io.c index b31f28416..d9375eac2 100644 --- a/libbb/udp_io.c +++ b/libbb/udp_io.c @@ -6,7 +6,6 @@ * * Licensed under GPL version 2, see file LICENSE in this tarball for details. */ - #include "libbb.h" /* @@ -32,22 +31,23 @@ send_to_from(int fd, void *buf, size_t len, int flags, 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; union { char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))]; -#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) +# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; -#endif +# 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); @@ -76,20 +76,26 @@ send_to_from(int fd, void *buf, size_t len, int flags, 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) +# 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); @@ -106,15 +112,16 @@ recv_from_to(int fd, void *buf, size_t len, int flags, 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) +# if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; -#endif +# endif } u; struct cmsghdr *cmsgptr; struct msghdr msg; @@ -135,6 +142,8 @@ recv_from_to(int fd, void *buf, size_t len, int flags, 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; @@ -143,25 +152,27 @@ recv_from_to(int fd, void *buf, size_t len, int flags, if (cmsgptr->cmsg_level == IPPROTO_IP && cmsgptr->cmsg_type == IP_PKTINFO ) { -#define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) ) +# define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) ) to->sa_family = AF_INET; - ((struct sockaddr_in*)to)->sin_addr = pktinfo(cmsgptr)->ipi_addr; - /* ((struct sockaddr_in*)to)->sin_port = 123; */ -#undef pktinfo + /*to4->sin_addr = pktinfo(cmsgptr)->ipi_addr; - may be unaligned */ + memcpy(&to4->sin_addr, &pktinfo(cmsgptr)->ipi_addr, sizeof(to4->sin_addr)); + /*to4->sin_port = 123; - this data is not supplied by kernel */ +# undef pktinfo 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)) ) +# define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) ) to->sa_family = AF_INET6; - ((struct sockaddr_in6*)to)->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; - /* ((struct sockaddr_in6*)to)->sin6_port = 123; */ -#undef pktinfo + /*to6->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; - may be unaligned */ + memcpy(&to6->sin6_addr, &pktinfo(cmsgptr)->ipi6_addr, sizeof(to6->sin6_addr)); + /*to6->sin6_port = 123; */ +# undef pktinfo break; } -#endif +# endif } return recv_length; #endif |