Update rawsock code
This commit is contained in:
Joseph C. Lehner
parent
5d3933ce29
commit
3b1cdc7931
2 changed files with 124 additions and 154 deletions
281
rawsock.c
281
rawsock.c
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@ -1,181 +1,142 @@
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/ioctl.h>
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#include <net/bpf.h>
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#include <net/if.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <pcap.h>
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#ifndef MIN
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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#endif
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struct ethsock
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struct rawsock
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{
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int fd;
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pcap_t *pcap;
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struct timeval timeout;
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int fd;
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};
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static int init_filter(struct ethsock *sock, int protocol, int mtu)
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struct rawsock *rawsock_create(const char *interface)
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{
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struct bpf_program prog;
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struct bpf_insn insns[] = {
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BPF_STMT(BPF_LD+BPF_H+BPF_ABS, 12),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, protocol, 0, 1),
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BPF_STMT(BPF_RET+BPF_K, mtu),
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BPF_STMT(BPF_RET+BPF_K, 0)
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};
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prog.bf_insns = insns;
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prog.bf_len = sizeof(insns) / sizeof(insns[0]);
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if (ioctl(sock->fd, BIOCSETFNR, &prog) != 0) {
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perror("ioctl(BIOCSETFNR)");
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return -1;
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}
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return 0;
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}
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static int get_mtu(struct ifreq *ifr)
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{
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int fd, stat;
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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perror("socket");
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return -1;
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}
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stat = ioctl(fd, SIOCGIFMTU, ifr);
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if (stat < 0) {
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perror("ioctl(SIOCGIFMTU)");
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stat = -1;
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} else {
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stat = 0;
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}
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close(fd);
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return stat;
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}
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int ethsock_create(struct ethsock *sock, const char *interface, int protocol)
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{
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struct ifreq ifr;
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struct bpf_program bf;
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int i, val;
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char buf[12];
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for (i = 0; i < 100; ++i) {
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sprintf(buf, "/dev/bpf%d", i);
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sock->fd = open(buf, O_RDWR);
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if (sock->fd != -1) {
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break;
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}
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}
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if (sock->fd == -1) {
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fprintf(stderr, "Failed to open bpf device\n");
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return -1;
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}
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strncpy(ifr.ifr_name, interface, IFNAMSIZ - 1);
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if (ioctl(sock->fd, BIOCSETIF, &ifr) != 0) {
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perror("ioctl(BIOCSETIF)");
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return -1;
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}
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val = 1;
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if (ioctl(sock->fd, BIOCIMMEDIATE, &val) != 0) {
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perror("ioctl(BIOCIMMEDIATE)");
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return -1;
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}
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if (ioctl(sock->fd, BIOCGBLEN, &val) != 0) {
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perror("ioctl(BIOCGBLEN)");
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return -1;
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}
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if (get_mtu(&ifr) != 0) {
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return -1;
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}
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if (init_filter(sock, protocol, ifr.ifr_mtu) != 0) {
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return -1;
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}
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sock->timeout.tv_sec = 0;
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sock->timeout.tv_usec = 0;
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return 0;
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}
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int ethsock_close(struct ethsock *sock)
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{
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close(sock->fd);
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return 0;
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}
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int ethsock_set_timeout(struct ethsock *sock, unsigned msec)
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{
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sock->timeout.tv_sec = msec / 1000;
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sock->timeout.tv_usec = (msec % 1000) * 1000;
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return 0;
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}
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ssize_t ethsock_read(struct ethsock *sock, void *buf, size_t size)
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{
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struct bpf_hdr *bh;
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ssize_t len;
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fd_set fds;
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char errbuf[PCAP_ERRBUF_SIZE];
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struct bpf_program fp;
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struct rawsock *sock;
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int err;
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sock = malloc(sizeof(struct rawsock));
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if (!sock) {
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perror("malloc");
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return NULL;
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}
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errbuf[0] = '\0';
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sock->pcap = pcap_open_live(interface, BUFSIZ, 1, 1, errbuf);
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if (!sock->pcap) {
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fprintf(stderr, "pcap_open_live: %s\n", errbuf);
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goto cleanup_malloc;
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}
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if (*errbuf) {
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fprintf(stderr, "Warning: %s.\n", errbuf);
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}
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if (pcap_datalink(sock->pcap) != DLT_EN10MB) {
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fprintf(stderr, "Interface %s not supported.\n", interface);
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goto cleanup_pcap;
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}
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err = pcap_compile(sock->pcap, &fp, "ether proto 0x0912", 0,
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PCAP_NETMASK_UNKNOWN);
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if (err) {
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pcap_perror(sock->pcap, "pcap_compile");
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goto cleanup_pcap;
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}
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if ((err = pcap_setfilter(sock->pcap, &fp))) {
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pcap_perror(sock->pcap, "pcap_setfilter");
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goto cleanup_pcap;
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}
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sock->fd = pcap_get_selectable_fd(sock->pcap);
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if (sock->fd == -1) {
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fprintf(stderr, "No selectable file descriptor available.\n");
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goto cleanup_pcap;
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}
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return sock;
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cleanup_pcap:
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pcap_close(sock->pcap);
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cleanup_malloc:
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free(sock);
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return NULL;
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}
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int rawsock_recv(struct rawsock *sock, uint8_t **buffer, unsigned *size)
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{
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struct pcap_pkthdr* hdr;
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int status;
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fd_set fds;
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if (sock->timeout.tv_sec || sock->timeout.tv_usec) {
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FD_ZERO(&fds);
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FD_SET(sock->fd, &fds);
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err = select(sock->fd + 1, &fds, NULL, NULL, &sock->timeout);
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if (err == -1) {
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status = select(sock->fd + 1, &fds, NULL, NULL, &sock->timeout);
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if (status == -1) {
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perror("select");
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return -1;
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} else if (!err) {
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return 0;
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}
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}
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len = read(sock->fd, buf, size);
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if (len < 0) {
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perror("read");
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}
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bh = (struct bpf_hdr*)buf;
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len = MIN(size, bh->bh_datalen);
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memmove(buf, (char*)buf + bh->bh_hdrlen, len);
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return len;
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}
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int main()
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{
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struct ethsock sock;
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ssize_t len;
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char buf[1024];
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if (ethsock_create(&sock, "en0", 0x0912) != 0) {
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} else if (status == 0) {
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return 1;
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}
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ethsock_set_timeout(&sock, 1000);
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len = ethsock_read(&sock, buf, sizeof(buf));
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if (len > 0) {
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write(1, buf, len);
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}
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ethsock_close(&sock);
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return len > 0 ? 0 : 1;
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status = pcap_next_ex(sock->pcap, &hdr, (const u_char**)buffer);
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switch (status) {
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case 1:
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status = 0;
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*size = hdr->caplen;
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break;
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case 0:
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status = 1;
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break;
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case -1:
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pcap_perror(sock->pcap, "pcap_next_ex");
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status = -1;
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break;
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default:
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fprintf(stderr, "pcap_next_ex: returned %d.\n", status);
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status = -1;
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break;
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}
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return status;
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}
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int rawsock_send(struct rawsock *sock, uint8_t *buffer, size_t size)
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{
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#if defined(_WIN32) || defined(_WIN64)
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if (pcap_sendpacket(sock->pcap, buffer, size) == 0) {
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return 0;
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} else {
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pcap_perror(sock->pcap, "pcap_sendpacket");
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return -1;
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}
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#else
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if (pcap_inject(sock->pcap, buffer, size) != size) {
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return 0;
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} else {
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pcap_perror(sock->pcap, "pcap_inject");
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return -1;
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}
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#endif
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}
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int rawsock_close(struct rawsock *sock)
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{
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pcap_close(sock->pcap);
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free(sock);
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return 0;
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}
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int rawsock_set_timeout(struct rawsock *sock, unsigned msec)
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{
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sock->timeout.tv_sec = msec / 1000;
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sock->timeout.tv_usec = (msec % 1000) * 1000;
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return 0;
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}
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9
rawsock.h
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9
rawsock.h
Normal file
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@ -0,0 +1,9 @@
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#include <stdint.h>
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struct rawsock;
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struct rawsock *rawsock_create(const char *interface);
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int rawsock_close(struct rawsock *sock);
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int rawsock_send(struct rawsock *sock, uint8_t *buffer, size_t size);
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int rawsock_recv(struct rawsock *sock, uint8_t **buffer, unsigned *size);
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int rawsock_set_timeout(struct rawsock *sock, unsigned msec);
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