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

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    Revision 815 - (hide 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 niro 532 /*
    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 niro 815 if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one,
    48     sizeof(one)) == -1) {
    49 niro 532 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 niro 815 recvfrom(pkt_fd, &iph, sizeof(iph), 0,
    204     (struct sockaddr *)&sll, &sllen);
    205 niro 532 }
    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     }