Contents of /tags/mkinitrd-6_1_9/busybox/libbb/udp_io.c
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Wed Oct 28 00:26:51 2009 UTC (14 years, 10 months ago) by niro
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File size: 4694 byte(s)
Wed Oct 28 00:26:51 2009 UTC (14 years, 10 months ago) by niro
File MIME type: text/plain
File size: 4694 byte(s)
tagged 'mkinitrd-6_1_9'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 2007 Denys 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 FAST_FUNC |
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 | ssize_t FAST_FUNC |
29 | send_to_from(int fd, void *buf, size_t len, int flags, |
30 | const struct sockaddr *to, |
31 | const struct sockaddr *from, |
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 | union { |
40 | char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
41 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) |
42 | char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
43 | #endif |
44 | } u; |
45 | struct cmsghdr* cmsgptr; |
46 | |
47 | if (from->sa_family != AF_INET |
48 | #if ENABLE_FEATURE_IPV6 |
49 | && from->sa_family != AF_INET6 |
50 | #endif |
51 | ) { |
52 | /* ANY local address */ |
53 | return sendto(fd, buf, len, flags, to, tolen); |
54 | } |
55 | |
56 | /* man recvmsg and man cmsg is needed to make sense of code below */ |
57 | |
58 | iov[0].iov_base = buf; |
59 | iov[0].iov_len = len; |
60 | |
61 | memset(&u, 0, sizeof(u)); |
62 | |
63 | memset(&msg, 0, sizeof(msg)); |
64 | msg.msg_name = (void *)(struct sockaddr *)to; /* or compiler will annoy us */ |
65 | msg.msg_namelen = tolen; |
66 | msg.msg_iov = iov; |
67 | msg.msg_iovlen = 1; |
68 | msg.msg_control = &u; |
69 | msg.msg_controllen = sizeof(u); |
70 | msg.msg_flags = flags; |
71 | |
72 | cmsgptr = CMSG_FIRSTHDR(&msg); |
73 | if (to->sa_family == AF_INET && from->sa_family == AF_INET) { |
74 | struct in_pktinfo *pktptr; |
75 | cmsgptr->cmsg_level = IPPROTO_IP; |
76 | cmsgptr->cmsg_type = IP_PKTINFO; |
77 | cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); |
78 | pktptr = (struct in_pktinfo *)(CMSG_DATA(cmsgptr)); |
79 | /* pktptr->ipi_ifindex = 0; -- already done by memset(cbuf...) */ |
80 | pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr; |
81 | } |
82 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) |
83 | else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) { |
84 | struct in6_pktinfo *pktptr; |
85 | cmsgptr->cmsg_level = IPPROTO_IPV6; |
86 | cmsgptr->cmsg_type = IPV6_PKTINFO; |
87 | cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); |
88 | pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr)); |
89 | /* pktptr->ipi6_ifindex = 0; -- already done by memset(cbuf...) */ |
90 | pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr; |
91 | } |
92 | #endif |
93 | msg.msg_controllen = cmsgptr->cmsg_len; |
94 | |
95 | return sendmsg(fd, &msg, flags); |
96 | #endif |
97 | } |
98 | |
99 | /* NB: this will never set port# in 'to'! |
100 | * _Only_ IP/IPv6 address part of 'to' is _maybe_ modified. |
101 | * Typical usage is to preinit 'to' with "default" value |
102 | * before calling recv_from_to(). */ |
103 | ssize_t FAST_FUNC |
104 | recv_from_to(int fd, void *buf, size_t len, int flags, |
105 | struct sockaddr *from, struct sockaddr *to, |
106 | socklen_t sa_size) |
107 | { |
108 | #ifndef IP_PKTINFO |
109 | return recvfrom(fd, buf, len, flags, from, &sa_size); |
110 | #else |
111 | /* man recvmsg and man cmsg is needed to make sense of code below */ |
112 | struct iovec iov[1]; |
113 | union { |
114 | char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
115 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) |
116 | char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
117 | #endif |
118 | } u; |
119 | struct cmsghdr *cmsgptr; |
120 | struct msghdr msg; |
121 | ssize_t recv_length; |
122 | |
123 | iov[0].iov_base = buf; |
124 | iov[0].iov_len = len; |
125 | |
126 | memset(&msg, 0, sizeof(msg)); |
127 | msg.msg_name = (struct sockaddr *)from; |
128 | msg.msg_namelen = sa_size; |
129 | msg.msg_iov = iov; |
130 | msg.msg_iovlen = 1; |
131 | msg.msg_control = &u; |
132 | msg.msg_controllen = sizeof(u); |
133 | |
134 | recv_length = recvmsg(fd, &msg, flags); |
135 | if (recv_length < 0) |
136 | return recv_length; |
137 | |
138 | /* Here we try to retrieve destination IP and memorize it */ |
139 | for (cmsgptr = CMSG_FIRSTHDR(&msg); |
140 | cmsgptr != NULL; |
141 | cmsgptr = CMSG_NXTHDR(&msg, cmsgptr) |
142 | ) { |
143 | if (cmsgptr->cmsg_level == IPPROTO_IP |
144 | && cmsgptr->cmsg_type == IP_PKTINFO |
145 | ) { |
146 | #define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) ) |
147 | to->sa_family = AF_INET; |
148 | ((struct sockaddr_in*)to)->sin_addr = pktinfo(cmsgptr)->ipi_addr; |
149 | /* ((struct sockaddr_in*)to)->sin_port = 123; */ |
150 | #undef pktinfo |
151 | break; |
152 | } |
153 | #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) |
154 | if (cmsgptr->cmsg_level == IPPROTO_IPV6 |
155 | && cmsgptr->cmsg_type == IPV6_PKTINFO |
156 | ) { |
157 | #define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) ) |
158 | to->sa_family = AF_INET6; |
159 | ((struct sockaddr_in6*)to)->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; |
160 | /* ((struct sockaddr_in6*)to)->sin6_port = 123; */ |
161 | #undef pktinfo |
162 | break; |
163 | } |
164 | #endif |
165 | } |
166 | return recv_length; |
167 | #endif |
168 | } |