/*
* See if left->addr or left->next is %defaultroute and change it to IP.
*
* Returns:
* -1: failure
* 0: done
* 1: please call again: more to do
*/
static int resolve_defaultroute_one(struct starter_end *host,
struct starter_end *peer)
{
/*
* "left=" == host->addrtype and host->addr
* "leftnexthop=" == host->nexttype and host->nexthop
*/
/* What kind of result are we seeking? */
bool seeking_src = (host->addrtype == KH_DEFAULTROUTE);
bool seeking_gateway = (host->nexttype == KH_DEFAULTROUTE);
char msgbuf[RTNL_BUFSIZE];
bool has_dst = FALSE;
int query_again = 0;
if (!seeking_src && !seeking_gateway)
return 0; /* this end already figured out */
/* Fill netlink request */
netlink_query_init(msgbuf, host->addr_family);
if (host->nexttype == KH_IPADDR) {
/*
* My nexthop (gateway) is specified.
* We need to figure out our source IP to get there.
*/
netlink_query_add(msgbuf, RTA_DST, &host->nexthop);
has_dst = TRUE;
} else if (peer->addrtype == KH_IPADDR) {
/*
* Peer IP is specified.
* We may need to figure out source IP
* and gateway IP to get there.
*/
netlink_query_add(msgbuf, RTA_DST, &peer->addr);
has_dst = TRUE;
if (seeking_src && seeking_gateway &&
host->addr_family == AF_INET) {
/*
* If we have only peer IP and no gateway/src we must
* do two queries:
* 1) find out gateway for dst
* 2) find out src for that gateway
* Doing both in one query returns src for dst.
*
* (IPv6 returns link-local for gateway so we can and
* do seek both in one query.)
*/
seeking_src = FALSE;
query_again = 1;
}
}
if (has_dst && host->addrtype == KH_IPADDR) {
/* SRC works only with DST */
netlink_query_add(msgbuf, RTA_SRC, &host->addr);
}
/*
* If we have for example host=%defaultroute + peer=%any
* (no destination) the netlink reply will be full routing table.
* We must do two queries:
* 1) find out default gateway
* 2) find out src for that default gateway
*/
if (!has_dst) {
if (seeking_src && seeking_gateway) {
seeking_src = FALSE;
query_again = 1;
}
}
if (seeking_gateway) {
struct nlmsghdr *nlmsg = (struct nlmsghdr *)msgbuf;
nlmsg->nlmsg_flags |= NLM_F_DUMP;
}
if (verbose)
printf("\nseeking_src = %d, seeking_gateway = %d, has_dst = %d\n",
seeking_src, seeking_gateway, has_dst);
/* Send netlink get_route request */
ssize_t len = netlink_query(msgbuf);
if (len < 0)
return -1;
/* Parse reply */
struct nlmsghdr *nlmsg = (struct nlmsghdr *)msgbuf;
for (; NLMSG_OK(nlmsg, len); nlmsg = NLMSG_NEXT(nlmsg, len)) {
struct rtmsg *rtmsg;
struct rtattr *rtattr;
int rtlen;
char r_interface[IF_NAMESIZE+1];
char r_source[ADDRTOT_BUF];
char r_gateway[ADDRTOT_BUF];
char r_destination[ADDRTOT_BUF];
bool ignore;
if (nlmsg->nlmsg_type == NLMSG_DONE)
break;
if (nlmsg->nlmsg_type == NLMSG_ERROR) {
printf("netlink error\n");
return -1;
break;
}
/* ignore all but IPv4 and IPv6 */
rtmsg = (struct rtmsg *) NLMSG_DATA(nlmsg);
if (rtmsg->rtm_family != AF_INET &&
rtmsg->rtm_family != AF_INET6)
continue;
/* Parse one route entry */
r_interface[0] = r_interface[IF_NAMESIZE] = r_source[0] =
r_gateway[0] = r_destination[0] = '\0';
rtattr = (struct rtattr *) RTM_RTA(rtmsg);
rtlen = RTM_PAYLOAD(nlmsg);
for (;
RTA_OK(rtattr, rtlen);
rtattr = RTA_NEXT(rtattr, rtlen)) {
switch (rtattr->rta_type) {
case RTA_OIF:
if_indextoname(*(int *)RTA_DATA(rtattr),
r_interface);
break;
case RTA_PREFSRC:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_source, sizeof(r_source));
break;
case RTA_GATEWAY:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_gateway, sizeof(r_gateway));
break;
case RTA_DST:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_destination,
sizeof(r_destination));
break;
}
}
/*
* Ignore if not main table.
* Ignore ipsecX or mastX interfaces.
*/
ignore = rtmsg->rtm_table != RT_TABLE_MAIN ||
startswith(r_interface, "ipsec") ||
startswith(r_interface, "mast");
if (verbose) {
printf("dst %s via %s dev %s src %s table %d%s\n",
r_destination,
r_gateway,
r_interface,
r_source, rtmsg->rtm_table,
ignore ? "" : " (ignored)");
}
if (ignore)
continue;
if (seeking_src && r_source[0] != '\0') {
err_t err = tnatoaddr(r_source, 0, rtmsg->rtm_family,
&host->addr);
if (err == NULL) {
host->addrtype = KH_IPADDR;
seeking_src = FALSE;
if (verbose)
printf("set addr: %s\n", r_source);
} else if (verbose) {
printf("unknown source results from kernel (%s): %s\n",
r_source, err);
}
}
if (seeking_gateway && r_destination[0] == '\0' &&
(has_dst || r_source[0] == '\0')) {
if (r_gateway[0] == '\0' && r_interface[0] != '\0') {
/*
* Point-to-Point default gw without "via IP"
* Attempt to find r_gateway as the IP address
* on the interface.
*/
resolve_ppp_peer(r_interface, host->addr_family,
r_gateway);
}
if (r_gateway[0] != '\0') {
err_t err = tnatoaddr(r_gateway, 0,
rtmsg->rtm_family,
&host->nexthop);
if (err != NULL) {
printf("unknown gateway results from kernel: %s\n",
err);
} else {
/* Note: Use first even if multiple */
host->nexttype = KH_IPADDR;
seeking_gateway = FALSE;
if (verbose)
printf("set nexthop: %s\n",
r_gateway);
}
}
}
}
return query_again;
}
/*
* See if left->addr or left->next is %defaultroute and change it to IP.
*/
int resolve_defaultroute_one(struct starter_end *left,
struct starter_end *right)
{
/* TODO: this will probably not work with Point-to-Point links */
/* "left=" == left->addrtype + left->addr
* "leftnexthop=" == left->nexttype + left->nexthop
*/
/* What kind of result we want to parse? */
int parse_src = (left->addrtype == KH_DEFAULTROUTE);
int parse_gateway = (left->nexttype == KH_DEFAULTROUTE);
if (parse_src == 0 && parse_gateway == 0)
return 0;
/* Fill netlink request */
char msgbuf[RTNL_BUFSIZE];
int has_dst = 0;
netlink_query_init(msgbuf, left->addr_family);
if (left->nexttype == KH_IPADDR) { /* My nexthop is specified */
netlink_query_add(msgbuf, RTA_DST, &left->nexthop);
has_dst = 1;
} else if (right->addrtype == KH_IPADDR) { /* Peer IP is specified */
netlink_query_add(msgbuf, RTA_DST, &right->addr);
has_dst = 1;
}
if (has_dst && left->addrtype == KH_IPADDR) /* SRC works only with DST */
netlink_query_add(msgbuf, RTA_SRC, &left->addr);
/* If we have for example left=%defaultroute + right=%any, the netlink
* reply will be full routing table. We just want default gateway for the
* first run.
*/
if (has_dst == 0) {
struct nlmsghdr *nlmsg = (struct nlmsghdr *)msgbuf;
nlmsg->nlmsg_flags |= NLM_F_DUMP;
if (parse_gateway)
parse_src = 0;
}
if (verbose)
printf("\nparse_src = %d, parse_gateway = %d, has_dst = %d\n",
parse_src, parse_gateway, has_dst);
/* Send netlink get_route request */
int len = netlink_query(msgbuf);
if (len < 0)
return -1;
/* Parse reply */
struct nlmsghdr *nlmsg = (struct nlmsghdr *)msgbuf;
for (; NLMSG_OK(nlmsg, len); nlmsg = NLMSG_NEXT(nlmsg, len)) {
struct rtmsg *rtmsg;
struct rtattr *rtattr;
int rtlen;
char r_interface[IF_NAMESIZE];
char r_source[ADDRTOT_BUF];
char r_gateway[ADDRTOT_BUF];
char r_destination[ADDRTOT_BUF];
/* Check for IPv4 / IPv6 */
rtmsg = (struct rtmsg *) NLMSG_DATA(nlmsg);
if (rtmsg->rtm_family != AF_INET &&
rtmsg->rtm_family != AF_INET6)
continue;
/* Parse one route entry */
*r_interface = *r_source = *r_gateway = *r_destination = 0;
rtattr = (struct rtattr *) RTM_RTA(rtmsg);
rtlen = RTM_PAYLOAD(nlmsg);
for (; RTA_OK(rtattr, rtlen); rtattr = RTA_NEXT(rtattr, rtlen)) {
switch (rtattr->rta_type) {
case RTA_OIF:
if_indextoname(*(int *)RTA_DATA(rtattr), r_interface);
break;
case RTA_PREFSRC:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_source, sizeof(r_source));
break;
case RTA_GATEWAY:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_gateway, sizeof(r_gateway));
break;
case RTA_DST:
inet_ntop(rtmsg->rtm_family, RTA_DATA(rtattr),
r_destination, sizeof(r_destination));
break;
}
}
if (verbose)
printf("dst %s via %s dev %s src %s\n",
r_destination, r_gateway, r_interface, r_source);
err_t err;
if (parse_src && *r_source != 0) {
err = tnatoaddr(r_source, 0, rtmsg->rtm_family, &left->addr);
if (err == NULL) {
left->addrtype = KH_IPADDR;
parse_src = 0;
if (verbose)
printf("set addr: %s\n", r_source);
} else if (verbose)
printf("unknown source results from kernel: %s\n", err);
}
if (parse_gateway && *r_gateway != 0 && (has_dst || *r_source == 0)) {
err = tnatoaddr(r_gateway, 0, rtmsg->rtm_family, &left->nexthop);
if (err == NULL) {
left->nexttype = KH_IPADDR;
parse_gateway = 0; /* Use first if multiple */
if (verbose)
printf("set nexthop: %s\n", r_gateway);
} else if (verbose)
printf("unknown gateway results from kernel: %s\n", err);
}
}
/* If we parsed and found default_gateway, we must do the request again
* to find out the source IP for that gateway.
*/
return has_dst == 0 && parse_gateway == 0;
}
