[1765] | 1 | /* vi: set sw=4 ts=4: */
|
---|
| 2 | /*
|
---|
| 3 | * Utility routines.
|
---|
| 4 | *
|
---|
| 5 | * Copyright (C) 2007 Denis Vlasenko
|
---|
| 6 | *
|
---|
| 7 | * Licensed under GPL version 2, see file LICENSE in this tarball for details.
|
---|
| 8 | */
|
---|
| 9 |
|
---|
| 10 | #include "libbb.h"
|
---|
| 11 |
|
---|
| 12 | /*
|
---|
| 13 | * This asks kernel to let us know dst addr/port of incoming packets
|
---|
| 14 | * We don't check for errors here. Not supported == won't be used
|
---|
| 15 | */
|
---|
| 16 | void
|
---|
| 17 | socket_want_pktinfo(int fd)
|
---|
| 18 | {
|
---|
| 19 | #ifdef IP_PKTINFO
|
---|
| 20 | setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int));
|
---|
| 21 | #endif
|
---|
| 22 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
|
---|
| 23 | setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &const_int_1, sizeof(int));
|
---|
| 24 | #endif
|
---|
| 25 | }
|
---|
| 26 |
|
---|
| 27 |
|
---|
| 28 | #ifdef UNUSED
|
---|
| 29 | ssize_t
|
---|
| 30 | send_to_from(int fd, void *buf, size_t len, int flags,
|
---|
| 31 | const struct sockaddr *from, const struct sockaddr *to,
|
---|
| 32 | socklen_t tolen)
|
---|
| 33 | {
|
---|
| 34 | #ifndef IP_PKTINFO
|
---|
| 35 | return sendto(fd, buf, len, flags, to, tolen);
|
---|
| 36 | #else
|
---|
| 37 | struct iovec iov[1];
|
---|
| 38 | struct msghdr msg;
|
---|
| 39 | char cbuf[sizeof(struct in_pktinfo)
|
---|
| 40 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
|
---|
| 41 | | sizeof(struct in6_pktinfo) /* (a|b) is poor man's max(a,b) */
|
---|
| 42 | #endif
|
---|
| 43 | ];
|
---|
| 44 | struct cmsghdr* cmsgptr;
|
---|
| 45 |
|
---|
| 46 | if (from->sa_family != AF_INET
|
---|
| 47 | #if ENABLE_FEATURE_IPV6
|
---|
| 48 | && from->sa_family != AF_INET6
|
---|
| 49 | #endif
|
---|
| 50 | ) {
|
---|
| 51 | /* ANY local address */
|
---|
| 52 | return sendto(fd, buf, len, flags, to, tolen);
|
---|
| 53 | }
|
---|
| 54 |
|
---|
| 55 | /* man recvmsg and man cmsg is needed to make sense of code below */
|
---|
| 56 |
|
---|
| 57 | iov[0].iov_base = buf;
|
---|
| 58 | iov[0].iov_len = len;
|
---|
| 59 |
|
---|
| 60 | memset(cbuf, 0, sizeof(cbuf));
|
---|
| 61 |
|
---|
| 62 | memset(&msg, 0, sizeof(msg));
|
---|
| 63 | msg.msg_name = (void *)(struct sockaddr *)to; /* or compiler will annoy us */
|
---|
| 64 | msg.msg_namelen = tolen;
|
---|
| 65 | msg.msg_iov = iov;
|
---|
| 66 | msg.msg_iovlen = 1;
|
---|
| 67 | msg.msg_control = cbuf;
|
---|
| 68 | msg.msg_controllen = sizeof(cbuf);
|
---|
| 69 | msg.msg_flags = flags;
|
---|
| 70 |
|
---|
| 71 | cmsgptr = CMSG_FIRSTHDR(&msg);
|
---|
| 72 | if (to->sa_family == AF_INET && from->sa_family == AF_INET) {
|
---|
| 73 | struct in_pktinfo *pktptr;
|
---|
| 74 | cmsgptr->cmsg_level = IPPROTO_IP;
|
---|
| 75 | cmsgptr->cmsg_type = IP_PKTINFO;
|
---|
| 76 | cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
|
---|
| 77 | pktptr = (struct in_pktinfo *)(CMSG_DATA(cmsgptr));
|
---|
| 78 | /* pktptr->ipi_ifindex = 0; -- already done by memset(cbuf...) */
|
---|
| 79 | pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr;
|
---|
| 80 | }
|
---|
| 81 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
|
---|
| 82 | else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) {
|
---|
| 83 | struct in6_pktinfo *pktptr;
|
---|
| 84 | cmsgptr->cmsg_level = IPPROTO_IPV6;
|
---|
| 85 | cmsgptr->cmsg_type = IPV6_PKTINFO;
|
---|
| 86 | cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
|
---|
| 87 | pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr));
|
---|
| 88 | /* pktptr->ipi6_ifindex = 0; -- already done by memset(cbuf...) */
|
---|
| 89 | pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr;
|
---|
| 90 | }
|
---|
| 91 | #endif
|
---|
| 92 | return sendmsg(fd, &msg, flags);
|
---|
| 93 | #endif
|
---|
| 94 | }
|
---|
| 95 | #endif /* UNUSED */
|
---|
| 96 |
|
---|
| 97 | /* NB: this will never set port# in 'to'!
|
---|
| 98 | * _Only_ IP/IPv6 address part of 'to' is _maybe_ modified.
|
---|
| 99 | * Typical usage is to preinit 'to' with "default" value
|
---|
| 100 | * before calling recv_from_to(). */
|
---|
| 101 | ssize_t
|
---|
| 102 | recv_from_to(int fd, void *buf, size_t len, int flags,
|
---|
| 103 | struct sockaddr *from, struct sockaddr *to,
|
---|
| 104 | socklen_t sa_size)
|
---|
| 105 | {
|
---|
| 106 | #ifndef IP_PKTINFO
|
---|
| 107 | return recvfrom(fd, buf, len, flags, from, &sa_size);
|
---|
| 108 | #else
|
---|
| 109 | /* man recvmsg and man cmsg is needed to make sense of code below */
|
---|
| 110 | struct iovec iov[1];
|
---|
| 111 | union {
|
---|
| 112 | char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
|
---|
| 113 | char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
|
---|
| 114 | } u;
|
---|
| 115 | struct cmsghdr *cmsgptr;
|
---|
| 116 | struct msghdr msg;
|
---|
| 117 | socklen_t recv_length;
|
---|
| 118 |
|
---|
| 119 | iov[0].iov_base = buf;
|
---|
| 120 | iov[0].iov_len = len;
|
---|
| 121 |
|
---|
| 122 | memset(&msg, 0, sizeof(msg));
|
---|
| 123 | msg.msg_name = (struct sockaddr *)from;
|
---|
| 124 | msg.msg_namelen = sa_size;
|
---|
| 125 | msg.msg_iov = iov;
|
---|
| 126 | msg.msg_iovlen = 1;
|
---|
| 127 | msg.msg_control = &u;
|
---|
| 128 | msg.msg_controllen = sizeof(u);
|
---|
| 129 |
|
---|
| 130 | recv_length = recvmsg(fd, &msg, flags);
|
---|
| 131 | if (recv_length < 0)
|
---|
| 132 | return recv_length;
|
---|
| 133 |
|
---|
| 134 | /* Here we try to retrieve destination IP and memorize it */
|
---|
| 135 | for (cmsgptr = CMSG_FIRSTHDR(&msg);
|
---|
| 136 | cmsgptr != NULL;
|
---|
| 137 | cmsgptr = CMSG_NXTHDR(&msg, cmsgptr)
|
---|
| 138 | ) {
|
---|
| 139 | if (cmsgptr->cmsg_level == IPPROTO_IP
|
---|
| 140 | && cmsgptr->cmsg_type == IP_PKTINFO
|
---|
| 141 | ) {
|
---|
| 142 | #define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )
|
---|
| 143 | to->sa_family = AF_INET;
|
---|
| 144 | ((struct sockaddr_in*)to)->sin_addr = pktinfo(cmsgptr)->ipi_addr;
|
---|
| 145 | /* ((struct sockaddr_in*)to)->sin_port = 123; */
|
---|
| 146 | #undef pktinfo
|
---|
| 147 | break;
|
---|
| 148 | }
|
---|
| 149 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
|
---|
| 150 | if (cmsgptr->cmsg_level == IPPROTO_IPV6
|
---|
| 151 | && cmsgptr->cmsg_type == IPV6_PKTINFO
|
---|
| 152 | ) {
|
---|
| 153 | #define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
|
---|
| 154 | to->sa_family = AF_INET6;
|
---|
| 155 | ((struct sockaddr_in6*)to)->sin6_addr = pktinfo(cmsgptr)->ipi6_addr;
|
---|
| 156 | /* ((struct sockaddr_in6*)to)->sin6_port = 123; */
|
---|
| 157 | #undef pktinfo
|
---|
| 158 | break;
|
---|
| 159 | }
|
---|
| 160 | #endif
|
---|
| 161 | }
|
---|
| 162 | return recv_length;
|
---|
| 163 | #endif
|
---|
| 164 | }
|
---|