source: MondoRescue/branches/stable/mindi-busybox/networking/libiproute/iptunnel.c@ 1842

/* vi: set sw=4 ts=4: */
/*
 * iptunnel.c          "ip tunnel"
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 *
 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *
 * Changes:
 *
 * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
 * Rani Assaf <rani@magic.metawire.com> 980930: do not allow key for ipip/sit
 * Phil Karn <karn@ka9q.ampr.org>   990408: "pmtudisc" flag
 */

#include <netinet/ip.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <asm/types.h>
#ifndef __constant_htons
#define __constant_htons htons
#endif
#include <linux/if_tunnel.h>

#include "ip_common.h"  /* #include "libbb.h" is inside */
#include "rt_names.h"
#include "utils.h"


/* Dies on error */
static int do_ioctl_get_ifindex(char *dev)
{
    struct ifreq ifr;
    int fd;

    strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name));
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
    xioctl(fd, SIOCGIFINDEX, &ifr);
    close(fd);
    return ifr.ifr_ifindex;
}

static int do_ioctl_get_iftype(char *dev)
{
    struct ifreq ifr;
    int fd;
    int err;

    strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name));
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
    err = ioctl_or_warn(fd, SIOCGIFHWADDR, &ifr);
    close(fd);
    return err ? -1 : ifr.ifr_addr.sa_family;
}

static char *do_ioctl_get_ifname(int idx)
{
    struct ifreq ifr;
    int fd;
    int err;

    ifr.ifr_ifindex = idx;
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
    err = ioctl_or_warn(fd, SIOCGIFNAME, &ifr);
    close(fd);
    return err ? NULL : xstrndup(ifr.ifr_name, sizeof(ifr.ifr_name));
}

static int do_get_ioctl(const char *basedev, struct ip_tunnel_parm *p)
{
    struct ifreq ifr;
    int fd;
    int err;

    strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
    ifr.ifr_ifru.ifru_data = (void*)p;
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
    err = ioctl_or_warn(fd, SIOCGETTUNNEL, &ifr);
    close(fd);
    return err;
}

/* Dies on error, otherwise returns 0 */
static int do_add_ioctl(int cmd, const char *basedev, struct ip_tunnel_parm *p)
{
    struct ifreq ifr;
    int fd;

    if (cmd == SIOCCHGTUNNEL && p->name[0]) {
        strncpy(ifr.ifr_name, p->name, sizeof(ifr.ifr_name));
    } else {
        strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
    }
    ifr.ifr_ifru.ifru_data = (void*)p;
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
#if ENABLE_IOCTL_HEX2STR_ERROR
    /* #define magic will turn ioctl# into string */
    if (cmd == SIOCCHGTUNNEL)
        xioctl(fd, SIOCCHGTUNNEL, &ifr);
    else
        xioctl(fd, SIOCADDTUNNEL, &ifr);
#else
    xioctl(fd, cmd, &ifr);
#endif
    close(fd);
    return 0;
}

/* Dies on error, otherwise returns 0 */
static int do_del_ioctl(const char *basedev, struct ip_tunnel_parm *p)
{
    struct ifreq ifr;
    int fd;

    if (p->name[0]) {
        strncpy(ifr.ifr_name, p->name, sizeof(ifr.ifr_name));
    } else {
        strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
    }
    ifr.ifr_ifru.ifru_data = (void*)p;
    fd = xsocket(AF_INET, SOCK_DGRAM, 0);
    xioctl(fd, SIOCDELTUNNEL, &ifr);
    close(fd);
    return 0;
}

/* Dies on error */
static void parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
{
    static const char keywords[] ALIGN1 =
        "mode\0""ipip\0""ip/ip\0""gre\0""gre/ip\0""sit\0""ipv6/ip\0"
        "key\0""ikey\0""okey\0""seq\0""iseq\0""oseq\0"
        "csum\0""icsum\0""ocsum\0""nopmtudisc\0""pmtudisc\0"
        "remote\0""any\0""local\0""dev\0"
        "ttl\0""inherit\0""tos\0""dsfield\0"
        "name\0";
    enum {
        ARG_mode, ARG_ipip, ARG_ip_ip, ARG_gre, ARG_gre_ip, ARG_sit, ARG_ip6_ip,
        ARG_key, ARG_ikey, ARG_okey, ARG_seq, ARG_iseq, ARG_oseq,
        ARG_csum, ARG_icsum, ARG_ocsum, ARG_nopmtudisc, ARG_pmtudisc,
        ARG_remote, ARG_any, ARG_local, ARG_dev,
        ARG_ttl, ARG_inherit, ARG_tos, ARG_dsfield,
        ARG_name
    };
    int count = 0;
    char medium[IFNAMSIZ];
    int key;

    memset(p, 0, sizeof(*p));
    memset(&medium, 0, sizeof(medium));

    p->iph.version = 4;
    p->iph.ihl = 5;
#ifndef IP_DF
#define IP_DF 0x4000  /* Flag: "Don't Fragment" */
#endif
    p->iph.frag_off = htons(IP_DF);

    while (argc > 0) {
        key = index_in_strings(keywords, *argv);
        if (key == ARG_mode) {
            NEXT_ARG();
            key = index_in_strings(keywords, *argv);
            if (key == ARG_ipip ||
                key == ARG_ip_ip) {
                if (p->iph.protocol && p->iph.protocol != IPPROTO_IPIP) {
                    bb_error_msg_and_die("you managed to ask for more than one tunnel mode");
                }
                p->iph.protocol = IPPROTO_IPIP;
            } else if (key == ARG_gre ||
                   key == ARG_gre_ip) {
                if (p->iph.protocol && p->iph.protocol != IPPROTO_GRE) {
                    bb_error_msg_and_die("you managed to ask for more than one tunnel mode");
                }
                p->iph.protocol = IPPROTO_GRE;
            } else if (key == ARG_sit ||
                   key == ARG_ip6_ip) {
                if (p->iph.protocol && p->iph.protocol != IPPROTO_IPV6) {
                    bb_error_msg_and_die("you managed to ask for more than one tunnel mode");
                }
                p->iph.protocol = IPPROTO_IPV6;
            } else {
                bb_error_msg_and_die("cannot guess tunnel mode");
            }
        } else if (key == ARG_key) {
            unsigned uval;
            NEXT_ARG();
            p->i_flags |= GRE_KEY;
            p->o_flags |= GRE_KEY;
            if (strchr(*argv, '.'))
                p->i_key = p->o_key = get_addr32(*argv);
            else {
                if (get_unsigned(&uval, *argv, 0)<0) {
                    bb_error_msg_and_die("invalid value of \"key\"");
                }
                p->i_key = p->o_key = htonl(uval);
            }
        } else if (key == ARG_ikey) {
            unsigned uval;
            NEXT_ARG();
            p->i_flags |= GRE_KEY;
            if (strchr(*argv, '.'))
                p->o_key = get_addr32(*argv);
            else {
                if (get_unsigned(&uval, *argv, 0)<0) {
                    bb_error_msg_and_die("invalid value of \"ikey\"");
                }
                p->i_key = htonl(uval);
            }
        } else if (key == ARG_okey) {
            unsigned uval;
            NEXT_ARG();
            p->o_flags |= GRE_KEY;
            if (strchr(*argv, '.'))
                p->o_key = get_addr32(*argv);
            else {
                if (get_unsigned(&uval, *argv, 0)<0) {
                    bb_error_msg_and_die("invalid value of \"okey\"");
                }
                p->o_key = htonl(uval);
            }
        } else if (key == ARG_seq) {
            p->i_flags |= GRE_SEQ;
            p->o_flags |= GRE_SEQ;
        } else if (key == ARG_iseq) {
            p->i_flags |= GRE_SEQ;
        } else if (key == ARG_oseq) {
            p->o_flags |= GRE_SEQ;
        } else if (key == ARG_csum) {
            p->i_flags |= GRE_CSUM;
            p->o_flags |= GRE_CSUM;
        } else if (key == ARG_icsum) {
            p->i_flags |= GRE_CSUM;
        } else if (key == ARG_ocsum) {
            p->o_flags |= GRE_CSUM;
        } else if (key == ARG_nopmtudisc) {
            p->iph.frag_off = 0;
        } else if (key == ARG_pmtudisc) {
            p->iph.frag_off = htons(IP_DF);
        } else if (key == ARG_remote) {
            NEXT_ARG();
            key = index_in_strings(keywords, *argv);
            if (key != ARG_any)
                p->iph.daddr = get_addr32(*argv);
        } else if (key == ARG_local) {
            NEXT_ARG();
            key = index_in_strings(keywords, *argv);
            if (key != ARG_any)
                p->iph.saddr = get_addr32(*argv);
        } else if (key == ARG_dev) {
            NEXT_ARG();
            strncpy(medium, *argv, IFNAMSIZ-1);
        } else if (key == ARG_ttl) {
            unsigned uval;
            NEXT_ARG();
            key = index_in_strings(keywords, *argv);
            if (key != ARG_inherit) {
                if (get_unsigned(&uval, *argv, 0))
                    invarg(*argv, "TTL");
                if (uval > 255)
                    invarg(*argv, "TTL must be <=255");
                p->iph.ttl = uval;
            }
        } else if (key == ARG_tos ||
               key == ARG_dsfield) {
            uint32_t uval;
            NEXT_ARG();
            key = index_in_strings(keywords, *argv);
            if (key != ARG_inherit) {
                if (rtnl_dsfield_a2n(&uval, *argv))
                    invarg(*argv, "TOS");
                p->iph.tos = uval;
            } else
                p->iph.tos = 1;
        } else {
            if (key == ARG_name) {
                NEXT_ARG();
            }
            if (p->name[0])
                duparg2("name", *argv);
            strncpy(p->name, *argv, IFNAMSIZ);
            if (cmd == SIOCCHGTUNNEL && count == 0) {
                struct ip_tunnel_parm old_p;
                memset(&old_p, 0, sizeof(old_p));
                if (do_get_ioctl(*argv, &old_p))
                    exit(1);
                *p = old_p;
            }
        }
        count++;
        argc--;
        argv++;
    }

    if (p->iph.protocol == 0) {
        if (memcmp(p->name, "gre", 3) == 0)
            p->iph.protocol = IPPROTO_GRE;
        else if (memcmp(p->name, "ipip", 4) == 0)
            p->iph.protocol = IPPROTO_IPIP;
        else if (memcmp(p->name, "sit", 3) == 0)
            p->iph.protocol = IPPROTO_IPV6;
    }

    if (p->iph.protocol == IPPROTO_IPIP || p->iph.protocol == IPPROTO_IPV6) {
        if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
            bb_error_msg_and_die("keys are not allowed with ipip and sit");
        }
    }

    if (medium[0]) {
        p->link = do_ioctl_get_ifindex(medium);
    }

    if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
        p->i_key = p->iph.daddr;
        p->i_flags |= GRE_KEY;
    }
    if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
        p->o_key = p->iph.daddr;
        p->o_flags |= GRE_KEY;
    }
    if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
        bb_error_msg_and_die("broadcast tunnel requires a source address");
    }
}


/* Return value becomes exitcode. It's okay to not return at all */
static int do_add(int cmd, int argc, char **argv)
{
    struct ip_tunnel_parm p;

    parse_args(argc, argv, cmd, &p);

    if (p.iph.ttl && p.iph.frag_off == 0) {
        bb_error_msg_and_die("ttl != 0 and noptmudisc are incompatible");
    }

    switch (p.iph.protocol) {
    case IPPROTO_IPIP:
        return do_add_ioctl(cmd, "tunl0", &p);
    case IPPROTO_GRE:
        return do_add_ioctl(cmd, "gre0", &p);
    case IPPROTO_IPV6:
        return do_add_ioctl(cmd, "sit0", &p);
    default:
        bb_error_msg_and_die("cannot determine tunnel mode (ipip, gre or sit)");
    }
}

/* Return value becomes exitcode. It's okay to not return at all */
static int do_del(int argc, char **argv)
{
    struct ip_tunnel_parm p;

    parse_args(argc, argv, SIOCDELTUNNEL, &p);

    switch (p.iph.protocol) {
    case IPPROTO_IPIP:
        return do_del_ioctl("tunl0", &p);
    case IPPROTO_GRE:
        return do_del_ioctl("gre0", &p);
    case IPPROTO_IPV6:
        return do_del_ioctl("sit0", &p);
    default:
        return do_del_ioctl(p.name, &p);
    }
}

static void print_tunnel(struct ip_tunnel_parm *p)
{
    char s1[256];
    char s2[256];
    char s3[64];
    char s4[64];

    format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1));
    format_host(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2));
    inet_ntop(AF_INET, &p->i_key, s3, sizeof(s3));
    inet_ntop(AF_INET, &p->o_key, s4, sizeof(s4));

    printf("%s: %s/ip  remote %s  local %s ",
           p->name,
           p->iph.protocol == IPPROTO_IPIP ? "ip" :
           (p->iph.protocol == IPPROTO_GRE ? "gre" :
        (p->iph.protocol == IPPROTO_IPV6 ? "ipv6" : "unknown")),
           p->iph.daddr ? s1 : "any", p->iph.saddr ? s2 : "any");
    if (p->link) {
        char *n = do_ioctl_get_ifname(p->link);
        if (n) {
            printf(" dev %s ", n);
            free(n);
        }
    }
    if (p->iph.ttl)
        printf(" ttl %d ", p->iph.ttl);
    else
        printf(" ttl inherit ");
    if (p->iph.tos) {
        SPRINT_BUF(b1);
        printf(" tos");
        if (p->iph.tos & 1)
            printf(" inherit");
        if (p->iph.tos & ~1)
            printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
                   rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
    }
    if (!(p->iph.frag_off & htons(IP_DF)))
        printf(" nopmtudisc");

    if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
        printf(" key %s", s3);
    else if ((p->i_flags | p->o_flags) & GRE_KEY) {
        if (p->i_flags & GRE_KEY)
            printf(" ikey %s ", s3);
        if (p->o_flags & GRE_KEY)
            printf(" okey %s ", s4);
    }

    if (p->i_flags & GRE_SEQ)
        printf("%c  Drop packets out of sequence.\n", _SL_);
    if (p->i_flags & GRE_CSUM)
        printf("%c  Checksum in received packet is required.", _SL_);
    if (p->o_flags & GRE_SEQ)
        printf("%c  Sequence packets on output.", _SL_);
    if (p->o_flags & GRE_CSUM)
        printf("%c  Checksum output packets.", _SL_);
}

static void do_tunnels_list(struct ip_tunnel_parm *p)
{
    char name[IFNAMSIZ];
    unsigned long rx_bytes, rx_packets, rx_errs, rx_drops,
        rx_fifo, rx_frame,
        tx_bytes, tx_packets, tx_errs, tx_drops,
        tx_fifo, tx_colls, tx_carrier, rx_multi;
    int type;
    struct ip_tunnel_parm p1;
    char buf[512];
    FILE *fp = fopen_or_warn("/proc/net/dev", "r");

    if (fp == NULL) {
        return;
    }

    fgets(buf, sizeof(buf), fp);
    fgets(buf, sizeof(buf), fp);

    while (fgets(buf, sizeof(buf), fp) != NULL) {
        char *ptr;

        /*buf[sizeof(buf) - 1] = 0; - fgets is safe anyway */
        ptr = strchr(buf, ':');
        if (ptr == NULL ||
            (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
            bb_error_msg("wrong format of /proc/net/dev");
            return;
        }
        if (sscanf(ptr, "%lu%lu%lu%lu%lu%lu%lu%*d%lu%lu%lu%lu%lu%lu%lu",
               &rx_bytes, &rx_packets, &rx_errs, &rx_drops,
               &rx_fifo, &rx_frame, &rx_multi,
               &tx_bytes, &tx_packets, &tx_errs, &tx_drops,
               &tx_fifo, &tx_colls, &tx_carrier) != 14)
            continue;
        if (p->name[0] && strcmp(p->name, name))
            continue;
        type = do_ioctl_get_iftype(name);
        if (type == -1) {
            bb_error_msg("cannot get type of [%s]", name);
            continue;
        }
        if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
            continue;
        memset(&p1, 0, sizeof(p1));
        if (do_get_ioctl(name, &p1))
            continue;
        if ((p->link && p1.link != p->link) ||
            (p->name[0] && strcmp(p1.name, p->name)) ||
            (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
            (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
            (p->i_key && p1.i_key != p->i_key))
            continue;
        print_tunnel(&p1);
        puts("");
    }
}

/* Return value becomes exitcode. It's okay to not return at all */
static int do_show(int argc, char **argv)
{
    int err;
    struct ip_tunnel_parm p;

    parse_args(argc, argv, SIOCGETTUNNEL, &p);

    switch (p.iph.protocol) {
    case IPPROTO_IPIP:
        err = do_get_ioctl(p.name[0] ? p.name : "tunl0", &p);
        break;
    case IPPROTO_GRE:
        err = do_get_ioctl(p.name[0] ? p.name : "gre0", &p);
        break;
    case IPPROTO_IPV6:
        err = do_get_ioctl(p.name[0] ? p.name : "sit0", &p);
        break;
    default:
        do_tunnels_list(&p);
        return 0;
    }
    if (err)
        return -1;

    print_tunnel(&p);
    puts("");
    return 0;
}

/* Return value becomes exitcode. It's okay to not return at all */
int do_iptunnel(int argc, char **argv)
{
    static const char keywords[] ALIGN1 =
        "add\0""change\0""delete\0""show\0""list\0""lst\0";
    enum { ARG_add = 0, ARG_change, ARG_del, ARG_show, ARG_list, ARG_lst };
    int key;

    if (argc) {
        key = index_in_substrings(keywords, *argv);
        if (key < 0)
            bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
        --argc;
        ++argv;
        if (key == ARG_add)
            return do_add(SIOCADDTUNNEL, argc, argv);
        if (key == ARG_change)
            return do_add(SIOCCHGTUNNEL, argc, argv);
        if (key == ARG_del)
            return do_del(argc, argv);
    }
    return do_show(argc, argv);
}