Arping代码

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/ip_icmp.h>
#include <time.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <netpacket/packet.h>
#include <netinet/ether.h>
#include <stdbool.h>
#include <sys/ioctl.h>

#define MAX_PINGCOUNT    3

//#define DEBUG 1
#ifdef DEBUG
#define DEBUGP(format,args...) fprintf(stdout, format, ##args)
#else
#define DEBUGP(format,args...)
#endif

#define MONOTONIC_US() ((unsigned)monotonic_us())

enum {
    DAD = 1,
    UNSOLICITED = 2,
    ADVERT = 4,
    QUIET = 8,
    QUIT_ON_REPLY = 16,
    BCAST_ONLY = 32,
    UNICASTING = 64
};

struct globals {
    struct in_addr src;
    struct in_addr dst;
    struct sockaddr_ll me;
    struct sockaddr_ll he;
    int sock_fd;

    int count; // = -1;
    unsigned last;
    unsigned timeout_us;
    unsigned start;

    unsigned sent;
    unsigned brd_sent;
    unsigned received;
    unsigned brd_recv;
    unsigned req_recv;
}G;

/* NB: unaligned parameter should be a pointer, aligned one -
 * a lvalue. This makes it more likely to not swap them by mistake
 */
#if defined(i386) || defined(__x86_64__)
# define move_from_unaligned_int(v, intp) ((v) = *(int*)(intp))
# define move_from_unaligned16(v, u16p) ((v) = *(uint16_t*)(u16p))
# define move_from_unaligned32(v, u32p) ((v) = *(uint32_t*)(u32p))
# define move_to_unaligned32(u32p, v) (*(uint32_t*)(u32p) = (v))
/* #elif ... - add your favorite arch */
#else
/* performs reasonably well (gcc usually inlines memcpy here) */
# define move_from_unaligned_int(v, intp) (memcpy(&(v), (intp), sizeof(int)))
# define move_from_unaligned16(v, u16p) (memcpy(&(v), (u16p), 2))
# define move_from_unaligned32(v, u32p) (memcpy(&(v), (u32p), 4))
# define move_to_unaligned32(u32p, v) do { \
    uint32_t __t = (v); \
    memcpy((u32p), &__t, 4); \
} while (0)
#endif

#define src (G.src )
#define dst (G.dst )
#define me (G.me )
#define he (G.he )
#define sock_fd (G.sock_fd )
#define count (G.count )
#define last (G.last )
#define timeout_us (G.timeout_us)
#define start (G.start )
#define sent (G.sent )
#define brd_sent (G.brd_sent )
#define received (G.received )
#define brd_recv (G.brd_recv )
#define req_recv (G.req_recv )
#define INIT_G() do { \
    memset(&G, 0, sizeof(G)); \
    count = -1; \
} while (0)

int quiet = 1;

static int setsockopt_bindtodevice(int fd, const char *iface)
{
    int r;
    struct ifreq ifr;
    strncpy(ifr.ifr_name, iface, IFNAMSIZ);
    /* NB: passing (iface, strlen(iface) + 1) does not
     * (maybe it works on _some_ kernels, but not on 2.6.26)
     * Actually, ifr_name is at offset 0, and in practice
     * just giving char[IFNAMSIZ] instead of struct ifreq works too.
     * But just in case it's not true on some obscure arch... */
    r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
    if (r)
        return -1;
    return r;
}

unsigned long long monotonic_us(void)
{
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return tv.tv_sec * 1000000ULL + tv.tv_usec;
}

static int sigaction_set(int signum, const struct sigaction *act)
{
    return sigaction(signum, act, NULL);
}

static void signal_SA_RESTART_empty_mask(int sig, void (*handler)(int))
{
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    /*sigemptyset(&sa.sa_mask);*/
    sa.sa_flags = SA_RESTART;
    sa.sa_handler = handler;
    sigaction_set(sig, &sa);
}

static int send_pack(struct in_addr *src_addr,
            struct in_addr *dst_addr, struct sockaddr_ll *ME,
            struct sockaddr_ll *HE)
{
    int err;
    unsigned char buf[256];
    struct arphdr *ah = (struct arphdr *) buf;
    unsigned char *p = (unsigned char *) (ah + 1);

    ah->ar_hrd = htons(ARPHRD_ETHER);
    ah->ar_pro = htons(ETH_P_IP);
    ah->ar_hln = ME->sll_halen;
    ah->ar_pln = 4;
    ah->ar_op = htons(ARPOP_REQUEST);

    p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
    p = mempcpy(p, src_addr, 4);

    p = mempcpy(p, &HE->sll_addr, ah->ar_hln);

    p = mempcpy(p, dst_addr, 4);

    err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
    if (err == p - buf) {
        last = MONOTONIC_US();
        sent++;
/*
        if (!(option_mask32 & UNICASTING))
            brd_sent++;
*/
    }
    return err;
}

static void finish(void)
{
    if (!quiet) {
        printf("Sent %u probe(s) (%u broadcast(s))\n"
            "Received %u repl%s"
            " (%u request(s), %u broadcast(s))\n",
            sent, brd_sent,
            received, (received == 1) ? "ies" : "y",
            req_recv, brd_recv);
    }

    close(sock_fd);
    sock_fd = -1;
}

static void catcher(void)
{
    unsigned now;

    now = MONOTONIC_US();
    if (start == 0)
        start = now;

    if (count == 0 || (timeout_us && (now - start) > timeout_us)){
        finish();
        return;
    }

    /* count < 0 means "infinite count" */
    if (count > 0)
        count--;

    if (last == 0 || (now - last) > 500000) {
        send_pack(&src, &dst, &me, &he);
        if(count == 0){
            finish();
            return;
        }
    }

    alarm(1);
}

static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
{
    struct arphdr *ah = (struct arphdr *) buf;
    unsigned char *p = (unsigned char *) (ah + 1);
    struct in_addr src_ip, dst_ip;
    /* moves below assume in_addr is 4 bytes big, ensure that */
    struct BUG_in_addr_must_be_4 {
        char BUG_in_addr_must_be_4[
            sizeof(struct in_addr) == 4 ? 1 : -1
        ];
        char BUG_s_addr_must_be_4[
            sizeof(src_ip.s_addr) == 4 ? 1 : -1
        ];
    };

    /* Filter out wild packets */
    if (FROM->sll_pkttype != PACKET_HOST
     && FROM->sll_pkttype != PACKET_BROADCAST
     && FROM->sll_pkttype != PACKET_MULTICAST)
        return false;

    /* Only these types are recognized */
    if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
        return false;

    /* ARPHRD check and this darned FDDI hack here :-( */
    if (ah->ar_hrd != htons(FROM->sll_hatype)
     && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
        return false;

    /* Protocol must be IP. */
    if (ah->ar_pro != htons(ETH_P_IP)
     || (ah->ar_pln != 4)
     || (ah->ar_hln != me.sll_halen)
     || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
        return false;

    move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
    move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);

    if (dst.s_addr != src_ip.s_addr)
        return false;
    if (1) {
        if ((src.s_addr != dst_ip.s_addr)
            || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
            return false;
    } else {
        /* DAD packet was:
           src_ip = 0 (or some src)
           src_hw = ME
           dst_ip = tested address
           dst_hw = <unspec>

           We fail, if receive request/reply with:
           src_ip = tested_address
           src_hw != ME
         if src_ip in request was not zero, check
           also that it matches to dst_ip, otherwise
           dst_ip/dst_hw do not matter.
         */
        if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
         || (src.s_addr && src.s_addr != dst_ip.s_addr))
            return false;
    }

    if (!quiet) {
        int s_printed = 0;

        printf("%scast re%s from %s [%s]",
            FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
            ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
            inet_ntoa(src_ip),
            ether_ntoa((struct ether_addr *) p));
        if (dst_ip.s_addr != src.s_addr) {
            printf("for %s ", inet_ntoa(dst_ip));
            s_printed = 1;
        }
        if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
            if (!s_printed)
                printf("for ");
            printf("[%s]",
                ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
        }

        if (last) {
            unsigned diff = MONOTONIC_US() - last;
            printf(" %u.%03ums\n", diff / 1000, diff % 1000);
        } else {
            printf(" UNSOLICITED?\n");
        }
        fflush(NULL);
    }
    received++;
    if (FROM->sll_pkttype != PACKET_HOST)
        brd_recv++;
    if (ah->ar_op == htons(ARPOP_REQUEST))
        req_recv++;

    return true;
}

static int getifindex(int sockfd, const char *device)
{
    struct ifreq ifr;
    int ret;

    memset(&ifr, 0, sizeof(ifr));
    strncpy(ifr.ifr_name, device, IFNAMSIZ);
    ret = ioctl(sockfd, SIOCGIFINDEX, &ifr);
    if(ret < 0)    return -1;

    me.sll_ifindex = ifr.ifr_ifindex;

    if(ioctl(sockfd, SIOCGIFFLAGS, (char *) &ifr) < 0){
        return -2;
    }

    if (!(ifr.ifr_flags & IFF_UP)) {
        return -3;
    }
    if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
        return -4;
    }

    return 0;
}

static int setsaddr(const char *device)
{
    struct sockaddr_in saddr;
    const int const_int_1 = 1;
    int probe_fd = socket(AF_INET, SOCK_DGRAM, 0);

    if(probe_fd < 0)    return -1;

    if(setsockopt_bindtodevice(probe_fd, device) < 0){
        close(probe_fd);
        return -2;
    }
    memset(&saddr, 0, sizeof(saddr));
    saddr.sin_family = AF_INET;

    /* Find IP address on this iface */
    socklen_t alen = sizeof(saddr);

    saddr.sin_port = htons(1025);
    saddr.sin_addr = dst;

    if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1){
        close(probe_fd);
        return -3;
    }
    if(connect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) < 0){
        close(probe_fd);
        return -4;
    }
    getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);

    if (saddr.sin_family != AF_INET){
        close(probe_fd);
        return -5;
    }
    src = saddr.sin_addr;

    close(probe_fd);
    return 0;
}

int arping(const char *device, const char *daddr, int pingcount)
{
    struct sockaddr_in saddr;
    struct ifreq ifr;
    char *source = NULL;
    const char *target;
    unsigned char packet[4096];
    socklen_t alen;
    char *err_str;
    int ret;

    INIT_G();

    sock_fd = socket(AF_PACKET, SOCK_DGRAM, 0);
    if(sock_fd < 0)    return -1;

    count = pingcount;
    timeout_us = 5 * 1000000 + 500000;
    target = daddr;

    if(getifindex(sock_fd, device) < 0){
        close(sock_fd);
        return -2;
    }

    dst.s_addr = inet_addr(target);

    if(setsaddr(device) < 0){
        close(sock_fd);
        return -3;
    }

    me.sll_family = AF_PACKET;
    me.sll_protocol = htons(ETH_P_ARP);
    if(bind(sock_fd, (struct sockaddr *) &me, sizeof(me)) < 0){
        close(sock_fd);
        return -4;
    }

    alen = sizeof(me);
    getsockname(sock_fd, (struct sockaddr *) &me, &alen);
    if (me.sll_halen == 0) {
        close(sock_fd);
        return -5;
    }
    he = me;
    memset(he.sll_addr, -1, he.sll_halen);

    if(!quiet){
        /* inet_ntoa uses static storage, can't use in same printf */
        printf("ARPING to %s", inet_ntoa(dst));
        printf(" from %s via %s\n", inet_ntoa(src), device);
    }

    signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
    signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);

    catcher();

    while (1) {
        sigset_t sset, osset;
        struct sockaddr_ll from;
        socklen_t alen = sizeof(from);
        int cc;

        if(count == 0 || sock_fd < 0)    break;
        cc = recvfrom(sock_fd, packet, sizeof(packet), 0, (struct sockaddr *) &from, &alen);
        if (cc < 0) {
            continue;
        }

        sigemptyset(&sset);
        sigaddset(&sset, SIGALRM);
        sigaddset(&sset, SIGINT);
        sigprocmask(SIG_BLOCK, &sset, &osset);
        recv_pack(packet, cc, &from);
        sigprocmask(SIG_SETMASK, &osset, NULL);
    }

    /* 没有收到任何应答 */
    if(received == 0)    return -6;

    return 0;
}

main(int argc, char **argv)
{
    if (argc != 3){
        return 1;
    }
    int reply;
    reply = arping(argv[2], argv[1], MAX_PINGCOUNT);
    if (reply == 0){
        fprintf(stdout, "Connect\n");
         return  0;
    }else{
        fprintf(stdout, "Disconect\n");
         return  2;
    }
}