source: MondoRescue/branches/2.2.5/mindi-busybox/libbb/udp_io.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 12 years ago

Update to busybox 1.7.2

  • Property svn:eol-style set to native
File size: 4.5 KB
Line 
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 */
16void
17socket_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
29ssize_t
30send_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(). */
101ssize_t
102recv_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}
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