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    Annotation of /trunk/mkinitrd-magellan/busybox/libbb/udp_io.c

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    Revision 984 - (hide annotations) (download)
    Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
    File MIME type: text/plain
    File size: 5283 byte(s) 
    -updated to busybox-1.16.1 and enabled blkid/uuid support in default config
    1 niro 816 /* 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     #include "libbb.h"
    10    
    11     /*
    12     * This asks kernel to let us know dst addr/port of incoming packets
    13     * We don't check for errors here. Not supported == won't be used
    14     */
    15     void FAST_FUNC
    16     socket_want_pktinfo(int fd)
    17     {
    18     #ifdef IP_PKTINFO
    19     setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int));
    20     #endif
    21     #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
    22     setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &const_int_1, sizeof(int));
    23     #endif
    24     }
    25    
    26    
    27     ssize_t FAST_FUNC
    28     send_to_from(int fd, void *buf, size_t len, int flags,
    29     const struct sockaddr *to,
    30     const struct sockaddr *from,
    31     socklen_t tolen)
    32     {
    33     #ifndef IP_PKTINFO
    34 niro 984 (void)from; /* suppress "unused from" warning */
    35 niro 816 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 niro 984 # if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
    42 niro 816 char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
    43 niro 984 # endif
    44 niro 816 } u;
    45     struct cmsghdr* cmsgptr;
    46    
    47     if (from->sa_family != AF_INET
    48 niro 984 # if ENABLE_FEATURE_IPV6
    49 niro 816 && from->sa_family != AF_INET6
    50 niro 984 # endif
    51 niro 816 ) {
    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 niro 984 /*pktptr->ipi_ifindex = 0; -- already done by memset(u...) */
    80     /* In general, CMSG_DATA() can be unaligned, but in this case
    81     * we know for sure it is sufficiently aligned:
    82     * CMSG_FIRSTHDR simply returns &u above,
    83     * and CMSG_DATA returns &u + size_t + int + int.
    84     * Thus direct assignment is ok:
    85     */
    86 niro 816 pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr;
    87     }
    88 niro 984 # if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
    89 niro 816 else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) {
    90     struct in6_pktinfo *pktptr;
    91     cmsgptr->cmsg_level = IPPROTO_IPV6;
    92     cmsgptr->cmsg_type = IPV6_PKTINFO;
    93     cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
    94     pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr));
    95 niro 984 /* pktptr->ipi6_ifindex = 0; -- already done by memset(u...) */
    96 niro 816 pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr;
    97     }
    98 niro 984 # endif
    99 niro 816 msg.msg_controllen = cmsgptr->cmsg_len;
    100    
    101     return sendmsg(fd, &msg, flags);
    102     #endif
    103     }
    104    
    105     /* NB: this will never set port# in 'to'!
    106     * _Only_ IP/IPv6 address part of 'to' is _maybe_ modified.
    107     * Typical usage is to preinit 'to' with "default" value
    108     * before calling recv_from_to(). */
    109     ssize_t FAST_FUNC
    110     recv_from_to(int fd, void *buf, size_t len, int flags,
    111     struct sockaddr *from, struct sockaddr *to,
    112     socklen_t sa_size)
    113     {
    114     #ifndef IP_PKTINFO
    115 niro 984 (void)to; /* suppress "unused to" warning */
    116 niro 816 return recvfrom(fd, buf, len, flags, from, &sa_size);
    117     #else
    118     /* man recvmsg and man cmsg is needed to make sense of code below */
    119     struct iovec iov[1];
    120     union {
    121     char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
    122 niro 984 # if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
    123 niro 816 char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
    124 niro 984 # endif
    125 niro 816 } u;
    126     struct cmsghdr *cmsgptr;
    127     struct msghdr msg;
    128     ssize_t recv_length;
    129    
    130     iov[0].iov_base = buf;
    131     iov[0].iov_len = len;
    132    
    133     memset(&msg, 0, sizeof(msg));
    134     msg.msg_name = (struct sockaddr *)from;
    135     msg.msg_namelen = sa_size;
    136     msg.msg_iov = iov;
    137     msg.msg_iovlen = 1;
    138     msg.msg_control = &u;
    139     msg.msg_controllen = sizeof(u);
    140    
    141     recv_length = recvmsg(fd, &msg, flags);
    142     if (recv_length < 0)
    143     return recv_length;
    144    
    145 niro 984 # define to4 ((struct sockaddr_in*)to)
    146     # define to6 ((struct sockaddr_in6*)to)
    147 niro 816 /* Here we try to retrieve destination IP and memorize it */
    148     for (cmsgptr = CMSG_FIRSTHDR(&msg);
    149     cmsgptr != NULL;
    150     cmsgptr = CMSG_NXTHDR(&msg, cmsgptr)
    151     ) {
    152     if (cmsgptr->cmsg_level == IPPROTO_IP
    153     && cmsgptr->cmsg_type == IP_PKTINFO
    154     ) {
    155 niro 984 # define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )
    156 niro 816 to->sa_family = AF_INET;
    157 niro 984 /*to4->sin_addr = pktinfo(cmsgptr)->ipi_addr; - may be unaligned */
    158     memcpy(&to4->sin_addr, &pktinfo(cmsgptr)->ipi_addr, sizeof(to4->sin_addr));
    159     /*to4->sin_port = 123; - this data is not supplied by kernel */
    160     # undef pktinfo
    161 niro 816 break;
    162     }
    163 niro 984 # if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
    164 niro 816 if (cmsgptr->cmsg_level == IPPROTO_IPV6
    165     && cmsgptr->cmsg_type == IPV6_PKTINFO
    166     ) {
    167 niro 984 # define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
    168 niro 816 to->sa_family = AF_INET6;
    169 niro 984 /*to6->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; - may be unaligned */
    170     memcpy(&to6->sin6_addr, &pktinfo(cmsgptr)->ipi6_addr, sizeof(to6->sin6_addr));
    171     /*to6->sin6_port = 123; */
    172     # undef pktinfo
    173 niro 816 break;
    174     }
    175 niro 984 # endif
    176 niro 816 }
    177     return recv_length;
    178     #endif
    179     }