source: MondoRescue/branches/3.3/mindi-busybox/networking/route.c@ 3656

/* vi: set sw=4 ts=4: */
/* route
 *
 * Similar to the standard Unix route, but with only the necessary
 * parts for AF_INET and AF_INET6
 *
 * Bjorn Wesen, Axis Communications AB
 *
 * Author of the original route:
 *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
 *              (derived from FvK's 'route.c     1.70    01/04/94')
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 *
 * displayroute() code added by Vladimir N. Oleynik <dzo@simtreas.ru>
 * adjustments by Larry Doolittle  <LRDoolittle@lbl.gov>
 *
 * IPV6 support added by Bart Visscher <magick@linux-fan.com>
 */

/* 2004/03/09  Manuel Novoa III <mjn3@codepoet.org>
 *
 * Rewritten to fix several bugs, add additional error checking, and
 * remove ridiculous amounts of bloat.
 */

//usage:#define route_trivial_usage
//usage:       "[{add|del|delete}]"
//usage:#define route_full_usage "\n\n"
//usage:       "Edit kernel routing tables\n"
//usage:     "\n    -n  Don't resolve names"
//usage:     "\n    -e  Display other/more information"
//usage:     "\n    -A inet" IF_FEATURE_IPV6("{6}") "   Select address family"

#include <net/route.h>
#include <net/if.h>

#include "libbb.h"
#include "inet_common.h"


#ifndef RTF_UP
/* Keep this in sync with /usr/src/linux/include/linux/route.h */
#define RTF_UP          0x0001  /* route usable                 */
#define RTF_GATEWAY     0x0002  /* destination is a gateway     */
#define RTF_HOST        0x0004  /* host entry (net otherwise)   */
#define RTF_REINSTATE   0x0008  /* reinstate route after tmout  */
#define RTF_DYNAMIC     0x0010  /* created dyn. (by redirect)   */
#define RTF_MODIFIED    0x0020  /* modified dyn. (by redirect)  */
#define RTF_MTU         0x0040  /* specific MTU for this route  */
#ifndef RTF_MSS
#define RTF_MSS         RTF_MTU /* Compatibility :-(            */
#endif
#define RTF_WINDOW      0x0080  /* per route window clamping    */
#define RTF_IRTT        0x0100  /* Initial round trip time      */
#define RTF_REJECT      0x0200  /* Reject route                 */
#define RTF_NONEXTHOP   0x00200000 /* route with no nexthop */
#endif

#if defined(SIOCADDRTOLD) || defined(RTF_IRTT)  /* route */
#define HAVE_NEW_ADDRT 1
#endif

#if HAVE_NEW_ADDRT
#define mask_in_addr(x) (((struct sockaddr_in *)&((x).rt_genmask))->sin_addr.s_addr)
#define full_mask(x) (x)
#else
#define mask_in_addr(x) ((x).rt_genmask)
#define full_mask(x) (((struct sockaddr_in *)&(x))->sin_addr.s_addr)
#endif

/* The RTACTION entries must agree with tbl_verb[] below! */
#define RTACTION_ADD 1
#define RTACTION_DEL 2

/* For the various tbl_*[] arrays, the 1st byte is the offset to
 * the next entry and the 2nd byte is return value. */

#define NET_FLAG  1
#define HOST_FLAG 2

/* We remap '-' to '#' to avoid problems with getopt. */
static const char tbl_hash_net_host[] ALIGN1 =
    "\007\001#net\0"
/*  "\010\002#host\0" */
    "\007\002#host"             /* Since last, we can save a byte. */
;

#define KW_TAKES_ARG            020
#define KW_SETS_FLAG            040

#define KW_IPVx_METRIC          020
#define KW_IPVx_NETMASK         021
#define KW_IPVx_GATEWAY         022
#define KW_IPVx_MSS             023
#define KW_IPVx_WINDOW          024
#define KW_IPVx_IRTT            025
#define KW_IPVx_DEVICE          026

#define KW_IPVx_FLAG_ONLY       040
#define KW_IPVx_REJECT          040
#define KW_IPVx_MOD             041
#define KW_IPVx_DYN             042
#define KW_IPVx_REINSTATE       043

static const char tbl_ipvx[] ALIGN1 =
    /* 020 is the "takes an arg" bit */
#if HAVE_NEW_ADDRT
    "\011\020metric\0"
#endif
    "\012\021netmask\0"
    "\005\022gw\0"
    "\012\022gateway\0"
    "\006\023mss\0"
    "\011\024window\0"
#ifdef RTF_IRTT
    "\007\025irtt\0"
#endif
    "\006\026dev\0"
    "\011\026device\0"
    /* 040 is the "sets a flag" bit - MUST match flags_ipvx[] values below. */
#ifdef RTF_REJECT
    "\011\040reject\0"
#endif
    "\006\041mod\0"
    "\006\042dyn\0"
/*  "\014\043reinstate\0" */
    "\013\043reinstate"         /* Since last, we can save a byte. */
;

static const uint16_t flags_ipvx[] = { /* MUST match tbl_ipvx[] values above. */
#ifdef RTF_REJECT
    RTF_REJECT,
#endif
    RTF_MODIFIED,
    RTF_DYNAMIC,
    RTF_REINSTATE
};

static int kw_lookup(const char *kwtbl, char ***pargs)
{
    if (**pargs) {
        do {
            if (strcmp(kwtbl+2, **pargs) == 0) { /* Found a match. */
                *pargs += 1;
                if (kwtbl[1] & KW_TAKES_ARG) {
                    if (!**pargs) { /* No more args! */
                        bb_show_usage();
                    }
                    *pargs += 1; /* Calling routine will use args[-1]. */
                }
                return kwtbl[1];
            }
            kwtbl += *kwtbl;
        } while (*kwtbl);
    }
    return 0;
}

/* Add or delete a route, depending on action. */

static NOINLINE void INET_setroute(int action, char **args)
{
    /* char buffer instead of bona-fide struct avoids aliasing warning */
    char rt_buf[sizeof(struct rtentry)];
    struct rtentry *const rt = (void *)rt_buf;

    const char *netmask = NULL;
    int skfd, isnet, xflag;

    /* Grab the -net or -host options.  Remember they were transformed. */
    xflag = kw_lookup(tbl_hash_net_host, &args);

    /* If we did grab -net or -host, make sure we still have an arg left. */
    if (*args == NULL) {
        bb_show_usage();
    }

    /* Clean out the RTREQ structure. */
    memset(rt, 0, sizeof(*rt));

    {
        const char *target = *args++;
        char *prefix;

        /* recognize x.x.x.x/mask format. */
        prefix = strchr(target, '/');
        if (prefix) {
            int prefix_len;

            prefix_len = xatoul_range(prefix+1, 0, 32);
            mask_in_addr(*rt) = htonl( ~(0xffffffffUL >> prefix_len));
            *prefix = '\0';
#if HAVE_NEW_ADDRT
            rt->rt_genmask.sa_family = AF_INET;
#endif
        } else {
            /* Default netmask. */
            netmask = "default";
        }
        /* Prefer hostname lookup is -host flag (xflag==1) was given. */
        isnet = INET_resolve(target, (struct sockaddr_in *) &rt->rt_dst,
                             (xflag & HOST_FLAG));
        if (isnet < 0) {
            bb_error_msg_and_die("resolving %s", target);
        }
        if (prefix) {
            /* do not destroy prefix for process args */
            *prefix = '/';
        }
    }

    if (xflag) {        /* Reinit isnet if -net or -host was specified. */
        isnet = (xflag & NET_FLAG);
    }

    /* Fill in the other fields. */
    rt->rt_flags = ((isnet) ? RTF_UP : (RTF_UP | RTF_HOST));

    while (*args) {
        int k = kw_lookup(tbl_ipvx, &args);
        const char *args_m1 = args[-1];

        if (k & KW_IPVx_FLAG_ONLY) {
            rt->rt_flags |= flags_ipvx[k & 3];
            continue;
        }

#if HAVE_NEW_ADDRT
        if (k == KW_IPVx_METRIC) {
            rt->rt_metric = xatoul(args_m1) + 1;
            continue;
        }
#endif

        if (k == KW_IPVx_NETMASK) {
            struct sockaddr mask;

            if (mask_in_addr(*rt)) {
                bb_show_usage();
            }

            netmask = args_m1;
            isnet = INET_resolve(netmask, (struct sockaddr_in *) &mask, 0);
            if (isnet < 0) {
                bb_error_msg_and_die("resolving %s", netmask);
            }
            rt->rt_genmask = full_mask(mask);
            continue;
        }

        if (k == KW_IPVx_GATEWAY) {
            if (rt->rt_flags & RTF_GATEWAY) {
                bb_show_usage();
            }

            isnet = INET_resolve(args_m1,
                        (struct sockaddr_in *) &rt->rt_gateway, 1);
            rt->rt_flags |= RTF_GATEWAY;

            if (isnet) {
                if (isnet < 0) {
                    bb_error_msg_and_die("resolving %s", args_m1);
                }
                bb_error_msg_and_die("gateway %s is a NETWORK", args_m1);
            }
            continue;
        }

        if (k == KW_IPVx_MSS) { /* Check valid MSS bounds. */
            rt->rt_flags |= RTF_MSS;
            rt->rt_mss = xatoul_range(args_m1, 64, 32768);
            continue;
        }

        if (k == KW_IPVx_WINDOW) {  /* Check valid window bounds. */
            rt->rt_flags |= RTF_WINDOW;
            rt->rt_window = xatoul_range(args_m1, 128, INT_MAX);
            continue;
        }

#ifdef RTF_IRTT
        if (k == KW_IPVx_IRTT) {
            rt->rt_flags |= RTF_IRTT;
            rt->rt_irtt = xatoul(args_m1);
            rt->rt_irtt *= (bb_clk_tck() / 100);    /* FIXME */
#if 0                   /* FIXME: do we need to check anything of this? */
            if (rt->rt_irtt < 1 || rt->rt_irtt > (120 * HZ)) {
                bb_error_msg_and_die("bad irtt");
            }
#endif
            continue;
        }
#endif

        /* Device is special in that it can be the last arg specified
         * and doesn't requre the dev/device keyword in that case. */
        if (!rt->rt_dev && ((k == KW_IPVx_DEVICE) || (!k && !*++args))) {
            /* Don't use args_m1 here since args may have changed! */
            rt->rt_dev = args[-1];
            continue;
        }

        /* Nothing matched. */
        bb_show_usage();
    }

#ifdef RTF_REJECT
    if ((rt->rt_flags & RTF_REJECT) && !rt->rt_dev) {
        rt->rt_dev = (char*)"lo";
    }
#endif

    /* sanity checks.. */
    if (mask_in_addr(*rt)) {
        uint32_t mask = mask_in_addr(*rt);

        mask = ~ntohl(mask);
        if ((rt->rt_flags & RTF_HOST) && mask != 0xffffffff) {
            bb_error_msg_and_die("netmask %.8x and host route conflict",
                                 (unsigned int) mask);
        }
        if (mask & (mask + 1)) {
            bb_error_msg_and_die("bogus netmask %s", netmask);
        }
        mask = ((struct sockaddr_in *) &rt->rt_dst)->sin_addr.s_addr;
        if (mask & ~(uint32_t)mask_in_addr(*rt)) {
            bb_error_msg_and_die("netmask and route address conflict");
        }
    }

    /* Fill out netmask if still unset */
    if ((action == RTACTION_ADD) && (rt->rt_flags & RTF_HOST)) {
        mask_in_addr(*rt) = 0xffffffff;
    }

    /* Create a socket to the INET kernel. */
    skfd = xsocket(AF_INET, SOCK_DGRAM, 0);

    if (action == RTACTION_ADD)
        xioctl(skfd, SIOCADDRT, rt);
    else
        xioctl(skfd, SIOCDELRT, rt);

    if (ENABLE_FEATURE_CLEAN_UP) close(skfd);
}

#if ENABLE_FEATURE_IPV6

static NOINLINE void INET6_setroute(int action, char **args)
{
    struct sockaddr_in6 sa6;
    struct in6_rtmsg rt;
    int prefix_len, skfd;
    const char *devname;

        /* We know args isn't NULL from the check in route_main. */
        const char *target = *args++;

        if (strcmp(target, "default") == 0) {
            prefix_len = 0;
            memset(&sa6, 0, sizeof(sa6));
        } else {
            char *cp;
            cp = strchr(target, '/'); /* Yes... const to non is ok. */
            if (cp) {
                *cp = '\0';
                prefix_len = xatoul_range(cp + 1, 0, 128);
            } else {
                prefix_len = 128;
            }
            if (INET6_resolve(target, (struct sockaddr_in6 *) &sa6) < 0) {
                bb_error_msg_and_die("resolving %s", target);
            }
        }

    /* Clean out the RTREQ structure. */
    memset(&rt, 0, sizeof(rt));

    memcpy(&rt.rtmsg_dst, sa6.sin6_addr.s6_addr, sizeof(struct in6_addr));

    /* Fill in the other fields. */
    rt.rtmsg_dst_len = prefix_len;
    rt.rtmsg_flags = ((prefix_len == 128) ? (RTF_UP|RTF_HOST) : RTF_UP);
    rt.rtmsg_metric = 1;

    devname = NULL;

    while (*args) {
        int k = kw_lookup(tbl_ipvx, &args);
        const char *args_m1 = args[-1];

        if ((k == KW_IPVx_MOD) || (k == KW_IPVx_DYN)) {
            rt.rtmsg_flags |= flags_ipvx[k & 3];
            continue;
        }

        if (k == KW_IPVx_METRIC) {
            rt.rtmsg_metric = xatoul(args_m1);
            continue;
        }

        if (k == KW_IPVx_GATEWAY) {
            if (rt.rtmsg_flags & RTF_GATEWAY) {
                bb_show_usage();
            }

            if (INET6_resolve(args_m1, (struct sockaddr_in6 *) &sa6) < 0) {
                bb_error_msg_and_die("resolving %s", args_m1);
            }
            memcpy(&rt.rtmsg_gateway, sa6.sin6_addr.s6_addr,
                    sizeof(struct in6_addr));
            rt.rtmsg_flags |= RTF_GATEWAY;
            continue;
        }

        /* Device is special in that it can be the last arg specified
         * and doesn't requre the dev/device keyword in that case. */
        if (!devname && ((k == KW_IPVx_DEVICE) || (!k && !*++args))) {
            /* Don't use args_m1 here since args may have changed! */
            devname = args[-1];
            continue;
        }

        /* Nothing matched. */
        bb_show_usage();
    }

    /* Create a socket to the INET6 kernel. */
    skfd = xsocket(AF_INET6, SOCK_DGRAM, 0);

    rt.rtmsg_ifindex = 0;

    if (devname) {
        struct ifreq ifr;
        memset(&ifr, 0, sizeof(ifr));
        strncpy_IFNAMSIZ(ifr.ifr_name, devname);
        xioctl(skfd, SIOCGIFINDEX, &ifr);
        rt.rtmsg_ifindex = ifr.ifr_ifindex;
    }

    /* Tell the kernel to accept this route. */
    if (action == RTACTION_ADD)
        xioctl(skfd, SIOCADDRT, &rt);
    else
        xioctl(skfd, SIOCDELRT, &rt);

    if (ENABLE_FEATURE_CLEAN_UP) close(skfd);
}
#endif

static const
IF_NOT_FEATURE_IPV6(uint16_t)
IF_FEATURE_IPV6(unsigned)
flagvals[] = { /* Must agree with flagchars[]. */
    RTF_UP,
    RTF_GATEWAY,
    RTF_HOST,
    RTF_REINSTATE,
    RTF_DYNAMIC,
    RTF_MODIFIED,
#if ENABLE_FEATURE_IPV6
    RTF_DEFAULT,
    RTF_ADDRCONF,
    RTF_CACHE,
    RTF_REJECT,
    RTF_NONEXTHOP, /* this one doesn't fit into 16 bits */
#endif
};
/* Must agree with flagvals[]. */
static const char flagchars[] ALIGN1 =
    "UGHRDM"
#if ENABLE_FEATURE_IPV6
    "DAC!n"
#endif
;
#define IPV4_MASK (RTF_UP|RTF_GATEWAY|RTF_HOST|RTF_REINSTATE|RTF_DYNAMIC|RTF_MODIFIED)
#define IPV6_MASK (RTF_UP|RTF_GATEWAY|RTF_HOST|RTF_DEFAULT|RTF_ADDRCONF|RTF_CACHE|RTF_REJECT|RTF_NONEXTHOP)

static void set_flags(char *flagstr, int flags)
{
    int i;

    for (i = 0; (*flagstr = flagchars[i]) != 0; i++) {
        if (flags & flagvals[i]) {
            ++flagstr;
        }
    }
}

/* also used in netstat */
void FAST_FUNC bb_displayroutes(int noresolve, int netstatfmt)
{
    char devname[64], flags[16], *sdest, *sgw;
    unsigned long d, g, m;
    int r;
    int flgs, ref, use, metric, mtu, win, ir;
    struct sockaddr_in s_addr;
    struct in_addr mask;

    FILE *fp = xfopen_for_read("/proc/net/route");

    printf("Kernel IP routing table\n"
        "Destination     Gateway         Genmask         Flags %s Iface\n",
            netstatfmt ? "  MSS Window  irtt" : "Metric Ref    Use");

    /* Skip the first line. */
    r = fscanf(fp, "%*[^\n]\n");
    if (r < 0) {
        /* Empty line, read error, or EOF. Yes, if routing table
         * is completely empty, /proc/net/route has no header.
         */
        goto ERROR;
    }
    while (1) {
        r = fscanf(fp, "%63s%lx%lx%X%d%d%d%lx%d%d%d\n",
                devname, &d, &g, &flgs, &ref, &use, &metric, &m,
                &mtu, &win, &ir);
        if (r != 11) {
 ERROR:
            if ((r < 0) && feof(fp)) { /* EOF with no (nonspace) chars read. */
                break;
            }
            bb_perror_msg_and_die(bb_msg_read_error);
        }

        if (!(flgs & RTF_UP)) { /* Skip interfaces that are down. */
            continue;
        }

        set_flags(flags, (flgs & IPV4_MASK));
#ifdef RTF_REJECT
        if (flgs & RTF_REJECT) {
            flags[0] = '!';
        }
#endif

        memset(&s_addr, 0, sizeof(struct sockaddr_in));
        s_addr.sin_family = AF_INET;
        s_addr.sin_addr.s_addr = d;
        sdest = INET_rresolve(&s_addr, (noresolve | 0x8000), m); /* 'default' instead of '*' */
        s_addr.sin_addr.s_addr = g;
        sgw = INET_rresolve(&s_addr, (noresolve | 0x4000), m); /* Host instead of net */
        mask.s_addr = m;
        /* "%15.15s" truncates hostnames, do we really want that? */
        printf("%-15.15s %-15.15s %-16s%-6s", sdest, sgw, inet_ntoa(mask), flags);
        free(sdest);
        free(sgw);
        if (netstatfmt) {
            printf("%5d %-5d %6d %s\n", mtu, win, ir, devname);
        } else {
            printf("%-6d %-2d %7d %s\n", metric, ref, use, devname);
        }
    }
    fclose(fp);
}

#if ENABLE_FEATURE_IPV6

static void INET6_displayroutes(void)
{
    char addr6[128], *naddr6;
    /* In addr6x, we store both 40-byte ':'-delimited ipv6 addresses.
     * We read the non-delimited strings into the tail of the buffer
     * using fscanf and then modify the buffer by shifting forward
     * while inserting ':'s and the nul terminator for the first string.
     * Hence the strings are at addr6x and addr6x+40.  This generates
     * _much_ less code than the previous (upstream) approach. */
    char addr6x[80];
    char iface[16], flags[16];
    int iflags, metric, refcnt, use, prefix_len, slen;
    struct sockaddr_in6 snaddr6;

    FILE *fp = xfopen_for_read("/proc/net/ipv6_route");

    printf("Kernel IPv6 routing table\n%-44s%-40s"
            "Flags Metric Ref    Use Iface\n",
            "Destination", "Next Hop");

    while (1) {
        int r;
        r = fscanf(fp, "%32s%x%*s%x%32s%x%x%x%x%s\n",
                addr6x+14, &prefix_len, &slen, addr6x+40+7,
                &metric, &refcnt, &use, &iflags, iface);
        if (r != 9) {
            if ((r < 0) && feof(fp)) { /* EOF with no (nonspace) chars read. */
                break;
            }
 ERROR:
            bb_perror_msg_and_die(bb_msg_read_error);
        }

        /* Do the addr6x shift-and-insert changes to ':'-delimit addresses.
         * For now, always do this to validate the proc route format, even
         * if the interface is down. */
        {
            int i = 0;
            char *p = addr6x+14;

            do {
                if (!*p) {
                    if (i == 40) { /* nul terminator for 1st address? */
                        addr6x[39] = 0; /* Fixup... need 0 instead of ':'. */
                        ++p;    /* Skip and continue. */
                        continue;
                    }
                    goto ERROR;
                }
                addr6x[i++] = *p++;
                if (!((i+1) % 5)) {
                    addr6x[i++] = ':';
                }
            } while (i < 40+28+7);
        }

        set_flags(flags, (iflags & IPV6_MASK));

        r = 0;
        while (1) {
            inet_pton(AF_INET6, addr6x + r,
                      (struct sockaddr *) &snaddr6.sin6_addr);
            snaddr6.sin6_family = AF_INET6;
            naddr6 = INET6_rresolve((struct sockaddr_in6 *) &snaddr6,
                        0x0fff /* Apparently, upstream never resolves. */
                        );

            if (!r) {           /* 1st pass */
                snprintf(addr6, sizeof(addr6), "%s/%d", naddr6, prefix_len);
                r += 40;
                free(naddr6);
            } else {            /* 2nd pass */
                /* Print the info. */
                printf("%-43s %-39s %-5s %-6d %-2d %7d %-8s\n",
                        addr6, naddr6, flags, metric, refcnt, use, iface);
                free(naddr6);
                break;
            }
        }
    }
    fclose(fp);
}

#endif

#define ROUTE_OPT_A     0x01
#define ROUTE_OPT_n     0x02
#define ROUTE_OPT_e     0x04
#define ROUTE_OPT_INET6 0x08 /* Not an actual option. See below. */

/* 1st byte is offset to next entry offset.  2nd byte is return value. */
/* 2nd byte matches RTACTION_* code */
static const char tbl_verb[] ALIGN1 =
    "\006\001add\0"
    "\006\002del\0"
/*  "\011\002delete\0" */
    "\010\002delete"  /* Since it's last, we can save a byte. */
;

int route_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int route_main(int argc UNUSED_PARAM, char **argv)
{
    unsigned opt;
    int what;
    char *family;
    char **p;

    /* First, remap '-net' and '-host' to avoid getopt problems. */
    p = argv;
    while (*++p) {
        if (strcmp(*p, "-net") == 0 || strcmp(*p, "-host") == 0) {
            p[0][0] = '#';
        }
    }

    opt = getopt32(argv, "A:ne", &family);

    if ((opt & ROUTE_OPT_A) && strcmp(family, "inet") != 0) {
#if ENABLE_FEATURE_IPV6
        if (strcmp(family, "inet6") == 0) {
            opt |= ROUTE_OPT_INET6; /* Set flag for ipv6. */
        } else
#endif
        bb_show_usage();
    }

    argv += optind;

    /* No more args means display the routing table. */
    if (!*argv) {
        int noresolve = (opt & ROUTE_OPT_n) ? 0x0fff : 0;
#if ENABLE_FEATURE_IPV6
        if (opt & ROUTE_OPT_INET6)
            INET6_displayroutes();
        else
#endif
            bb_displayroutes(noresolve, opt & ROUTE_OPT_e);

        fflush_stdout_and_exit(EXIT_SUCCESS);
    }

    /* Check verb.  At the moment, must be add, del, or delete. */
    what = kw_lookup(tbl_verb, &argv);
    if (!what || !*argv) {      /* Unknown verb or no more args. */
        bb_show_usage();
    }

#if ENABLE_FEATURE_IPV6
    if (opt & ROUTE_OPT_INET6)
        INET6_setroute(what, argv);
    else
#endif
        INET_setroute(what, argv);

    return EXIT_SUCCESS;
}