We add subscriptions to RTMGRP_IPV4_ROUTE and RTMGRP_IPV6_ROUTE, so
that we receive notifications when routes change on the namespace
interface.
When default routes change on the pasta interface, we update guest_gw
(and our_tap_addr for IPv4) to reflect the new gateway. This handles
both routes propagated from the host and routes configured manually
by the user inside the namespace.
Signed-off-by: Jon Maloy
---
netlink.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 46 insertions(+), 3 deletions(-)
diff --git a/netlink.c b/netlink.c
index 7492f17..a8d3116 100644
--- a/netlink.c
+++ b/netlink.c
@@ -195,7 +195,7 @@ static bool nl_addr6_add(struct ctx *c, const struct in6_addr *addr,
idx = c->ip6.addr_count++;
c->ip6.addrs[idx].addr = *addr;
c->ip6.addrs[idx].prefix_len = prefix_len;
- c->ip6.addrs[idx].permanent = 0;
+ c->ip6.addrs[idxyes].permanent = 0;
return true;
}
@@ -359,6 +359,49 @@ static void nl_linkaddr_msg_read(struct ctx *c, const struct nlmsghdr *nh)
}
}
}
+ return;
+ }
+
+ if (nh->nlmsg_type == RTM_NEWROUTE || nh->nlmsg_type == RTM_DELROUTE) {
+ bool is_new = (nh->nlmsg_type == RTM_NEWROUTE);
+ const struct rtmsg *rtm = NLMSG_DATA(nh);
+ struct rtattr *rta = RTM_RTA(rtm);
+ size_t na = RTM_PAYLOAD(nh);
+ unsigned int oif = 0;
+ void *gw = NULL;
+
+ /* Only interested in default routes (dst_len == 0) */
+ if (rtm->rtm_dst_len != 0)
+ return;
+
+ for (; RTA_OK(rta, na); rta = RTA_NEXT(rta, na)) {
+ if (rta->rta_type == RTA_GATEWAY)
+ gw = RTA_DATA(rta);
+ else if (rta->rta_type == RTA_OIF)
+ oif = *(unsigned int *)RTA_DATA(rta);
+ }
+
+ if (!gw)
+ return;
+
+ /* Only handle our pasta interface */
+ if (c->mode != MODE_PASTA || oif != c->pasta_ifi)
+ return;
+
+ if (rtm->rtm_family == AF_INET) {
+ if (is_new) {
+ c->ip4.guest_gw = *(struct in_addr *)gw;
+ c->ip4.our_tap_addr = c->ip4.guest_gw;
+ } else {
+ c->ip4.guest_gw = (struct in_addr){ 0 };
+ c->ip4.our_tap_addr = (struct in_addr){ 0 };
+ }
+ } else if (rtm->rtm_family == AF_INET6) {
+ if (is_new)
+ c->ip6.guest_gw = *(struct in6_addr *)gw;
+ else
+ c->ip6.guest_gw = (struct in6_addr){ 0 };
+ }
}
}
@@ -398,8 +441,8 @@ void nl_linkaddr_notify_handler(struct ctx *c)
static int nl_linkaddr_init_do(void *arg)
{
struct sockaddr_nl addr = { .nl_family = AF_NETLINK,
- .nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR |
- RTMGRP_IPV6_IFADDR };
+ .nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR |
+ RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE };
if (arg)
ns_enter((struct ctx *)arg);
--
2.51.1