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    Contents of /trunk/mkinitrd-magellan/klibc/usr/kinit/ipconfig/packet.c

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    Revision 815 - (show annotations) (download)
    Fri Apr 24 18:32:46 2009 UTC (15 years ago) by niro
    File MIME type: text/plain
    File size: 5676 byte(s) 
    -updated to klibc-1.5.15
    1 /*
    2 * Packet socket handling glue.
    3 */
    4 #include <sys/types.h>
    5 #include <sys/socket.h>
    6 #include <stdio.h>
    7 #include <stdlib.h>
    8 #include <string.h>
    9 #include <unistd.h>
    10 #include <net/if_packet.h>
    11 #include <netinet/if_ether.h>
    12 #include <netinet/in.h>
    13 #include <netpacket/packet.h>
    14 #include <asm/byteorder.h>
    15 #include <arpa/inet.h>
    16 #include <netinet/ip.h>
    17 #include <netinet/udp.h>
    18
    19 #include "ipconfig.h"
    20 #include "netdev.h"
    21 #include "packet.h"
    22
    23 static int pkt_fd = -1;
    24
    25 uint16_t cfg_local_port = LOCAL_PORT;
    26 uint16_t cfg_remote_port = REMOTE_PORT;
    27
    28 int packet_open(void)
    29 {
    30 int fd, one = 1;
    31
    32 if (pkt_fd != -1)
    33 return pkt_fd;
    34
    35 /*
    36 * Get a PACKET socket for IP traffic.
    37 */
    38 fd = socket(AF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
    39 if (fd == -1) {
    40 perror("socket");
    41 return -1;
    42 }
    43
    44 /*
    45 * We want to broadcast
    46 */
    47 if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one,
    48 sizeof(one)) == -1) {
    49 perror("SO_BROADCAST");
    50 close(fd);
    51 fd = -1;
    52 }
    53
    54 pkt_fd = fd;
    55
    56 return fd;
    57 }
    58
    59 void packet_close(void)
    60 {
    61 close(pkt_fd);
    62 pkt_fd = -1;
    63 }
    64
    65 static unsigned int ip_checksum(uint16_t *hdr, int len)
    66 {
    67 unsigned int chksum = 0;
    68
    69 while (len) {
    70 chksum += *hdr++;
    71 chksum += *hdr++;
    72 len--;
    73 }
    74 chksum = (chksum & 0xffff) + (chksum >> 16);
    75 chksum = (chksum & 0xffff) + (chksum >> 16);
    76 return (~chksum) & 0xffff;
    77 }
    78
    79 struct header {
    80 struct iphdr ip;
    81 struct udphdr udp;
    82 } __attribute__ ((packed));
    83
    84 static struct header ipudp_hdrs = {
    85 .ip = {
    86 .ihl = 5,
    87 .version = IPVERSION,
    88 .frag_off = __constant_htons(IP_DF),
    89 .ttl = 64,
    90 .protocol = IPPROTO_UDP,
    91 .saddr = INADDR_ANY,
    92 .daddr = INADDR_BROADCAST,
    93 },
    94 .udp = {
    95 .source = __constant_htons(LOCAL_PORT),
    96 .dest = __constant_htons(REMOTE_PORT),
    97 .len = 0,
    98 .check = 0,
    99 },
    100 };
    101
    102 #ifdef IPC_DEBUG /* Only used by DEBUG(()) */
    103 static char *ntoa(uint32_t addr)
    104 {
    105 struct in_addr in = { addr };
    106 return inet_ntoa(in);
    107 }
    108 #endif
    109
    110 /*
    111 * Send a packet. The options are listed in iov[1...iov_len].
    112 * iov[0] is reserved for the bootp packet header.
    113 */
    114 int packet_send(struct netdev *dev, struct iovec *iov, int iov_len)
    115 {
    116 struct sockaddr_ll sll;
    117 struct msghdr msg = {
    118 .msg_name = &sll,
    119 .msg_namelen = sizeof(sll),
    120 .msg_iov = iov,
    121 .msg_iovlen = iov_len,
    122 .msg_control = NULL,
    123 .msg_controllen = 0,
    124 .msg_flags = 0
    125 };
    126 int i, len = 0;
    127
    128 if (cfg_local_port != LOCAL_PORT) {
    129 ipudp_hdrs.udp.source = htons(cfg_local_port);
    130 ipudp_hdrs.udp.dest = htons(cfg_remote_port);
    131 }
    132
    133 DEBUG(("\n udp src %d dst %d", ntohs(ipudp_hdrs.udp.source),
    134 ntohs(ipudp_hdrs.udp.dest)));
    135
    136 DEBUG(("\n ip src %s ", ntoa(ipudp_hdrs.ip.saddr)));
    137 DEBUG(("dst %s ", ntoa(ipudp_hdrs.ip.daddr)));
    138
    139 /*
    140 * Glue in the ip+udp header iovec
    141 */
    142 iov[0].iov_base = &ipudp_hdrs;
    143 iov[0].iov_len = sizeof(struct header);
    144
    145 for (i = 0; i < iov_len; i++)
    146 len += iov[i].iov_len;
    147
    148 sll.sll_family = AF_PACKET;
    149 sll.sll_protocol = htons(ETH_P_IP);
    150 sll.sll_ifindex = dev->ifindex;
    151 sll.sll_hatype = dev->hwtype;
    152 sll.sll_pkttype = PACKET_BROADCAST;
    153 sll.sll_halen = dev->hwlen;
    154 memcpy(sll.sll_addr, dev->hwbrd, dev->hwlen);
    155
    156 ipudp_hdrs.ip.tot_len = htons(len);
    157 ipudp_hdrs.ip.check = 0;
    158 ipudp_hdrs.ip.check = ip_checksum((uint16_t *) & ipudp_hdrs.ip,
    159 ipudp_hdrs.ip.ihl);
    160
    161 ipudp_hdrs.udp.len = htons(len - sizeof(struct iphdr));
    162
    163 DEBUG(("\n bytes %d\n", len));
    164
    165 return sendmsg(pkt_fd, &msg, 0);
    166 }
    167
    168 int packet_peek(int *ifindex)
    169 {
    170 struct sockaddr_ll sll;
    171 struct iphdr iph;
    172 int ret, sllen = sizeof(struct sockaddr_ll);
    173
    174 /*
    175 * Peek at the IP header.
    176 */
    177 ret = recvfrom(pkt_fd, &iph, sizeof(struct iphdr),
    178 MSG_PEEK, (struct sockaddr *)&sll, &sllen);
    179 if (ret == -1)
    180 return -1;
    181
    182 if (sll.sll_family != AF_PACKET)
    183 goto discard_pkt;
    184
    185 if (iph.ihl < 5 || iph.version != IPVERSION)
    186 goto discard_pkt;
    187
    188 *ifindex = sll.sll_ifindex;
    189
    190 return 0;
    191
    192 discard_pkt:
    193 packet_discard();
    194 return 0;
    195 }
    196
    197 void packet_discard(void)
    198 {
    199 struct iphdr iph;
    200 struct sockaddr_ll sll;
    201 socklen_t sllen = sizeof(sll);
    202
    203 recvfrom(pkt_fd, &iph, sizeof(iph), 0,
    204 (struct sockaddr *)&sll, &sllen);
    205 }
    206
    207 /*
    208 * Receive a bootp packet. The options are listed in iov[1...iov_len].
    209 * iov[0] must point to the bootp packet header.
    210 */
    211 int packet_recv(struct iovec *iov, int iov_len)
    212 {
    213 struct iphdr *ip, iph;
    214 struct udphdr *udp;
    215 struct msghdr msg = {
    216 .msg_name = NULL,
    217 .msg_namelen = 0,
    218 .msg_iov = iov,
    219 .msg_iovlen = iov_len,
    220 .msg_control = NULL,
    221 .msg_controllen = 0,
    222 .msg_flags = 0
    223 };
    224 int ret, iphl;
    225
    226 ret = recvfrom(pkt_fd, &iph, sizeof(struct iphdr),
    227 MSG_PEEK, NULL, NULL);
    228 if (ret == -1)
    229 return -1;
    230
    231 if (iph.ihl < 5 || iph.version != IPVERSION)
    232 goto discard_pkt;
    233
    234 iphl = iph.ihl * 4;
    235
    236 ip = malloc(iphl + sizeof(struct udphdr));
    237 if (!ip)
    238 goto discard_pkt;
    239
    240 udp = (struct udphdr *)((char *)ip + iphl);
    241
    242 iov[0].iov_base = ip;
    243 iov[0].iov_len = iphl + sizeof(struct udphdr);
    244
    245 ret = recvmsg(pkt_fd, &msg, 0);
    246 if (ret == -1)
    247 goto free_pkt;
    248
    249 DEBUG(("<- bytes %d ", ret));
    250
    251 if (ip_checksum((uint16_t *) ip, ip->ihl) != 0)
    252 goto free_pkt;
    253
    254 DEBUG(("\n ip src %s ", ntoa(ip->saddr)));
    255 DEBUG(("dst %s ", ntoa(ip->daddr)));
    256
    257 if (ntohs(ip->tot_len) > ret || ip->protocol != IPPROTO_UDP)
    258 goto free_pkt;
    259
    260 ret -= 4 * ip->ihl;
    261
    262 DEBUG(("\n udp src %d dst %d ", ntohs(udp->source),
    263 ntohs(udp->dest)));
    264
    265 if (udp->source != htons(cfg_remote_port) ||
    266 udp->dest != htons(cfg_local_port))
    267 goto free_pkt;
    268
    269 if (ntohs(udp->len) > ret)
    270 goto free_pkt;
    271
    272 ret -= sizeof(struct udphdr);
    273
    274 free(ip);
    275
    276 return ret;
    277
    278 free_pkt:
    279 free(ip);
    280 return 0;
    281
    282 discard_pkt:
    283 DEBUG(("discarded\n"));
    284 packet_discard();
    285 return 0;
    286 }