diff options
| author | Roy Marples <roy@marples.name> | 2019-11-10 20:39:52 +0000 |
|---|---|---|
| committer | Roy Marples <roy@marples.name> | 2019-11-10 20:40:20 +0000 |
| commit | 127863ec6d42807bd595515ad8a39f92c36030ec (patch) | |
| tree | 47bfa4ae6057464eb59896f93d9444fbf11496b2 /src/ipv6nd.c | |
| parent | 7857a08e7c28cb16368501da110ec6f2a8e36e46 (diff) | |
| download | dhcpcd-127863ec6d42807bd595515ad8a39f92c36030ec.tar.xz | |
RA: Warn if advertised MTU is greater than link MTU
Diffstat (limited to 'src/ipv6nd.c')
| -rw-r--r-- | src/ipv6nd.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/src/ipv6nd.c b/src/ipv6nd.c index 3cf69713..6033ee11 100644 --- a/src/ipv6nd.c +++ b/src/ipv6nd.c @@ -990,6 +990,7 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct dhcp_opt *dho; bool new_rap, new_data, has_address; uint32_t old_lifetime; + int ifmtu; __printflike(1, 2) void (*logfunc)(const char *, ...); #ifdef IPV6_MANAGETEMPADDR uint8_t new_ap; @@ -1274,22 +1275,30 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, case ND_OPT_MTU: if (len < sizeof(mtu)) { - logerrx("%s: short MTU option", ifp->name); + logfunc("%s: short MTU option", ifp->name); break; } memcpy(&mtu, p, sizeof(mtu)); mtu.nd_opt_mtu_mtu = ntohl(mtu.nd_opt_mtu_mtu); if (mtu.nd_opt_mtu_mtu < IPV6_MMTU) { - logerrx("%s: invalid MTU %d", + logfunc("%s: invalid MTU %d", ifp->name, mtu.nd_opt_mtu_mtu); break; } - rap->mtu = mtu.nd_opt_mtu_mtu; + ifmtu = if_getmtu(ifp); + if (ifmtu == -1) + logerr("if_getmtu"); + else if (mtu.nd_opt_mtu_mtu > (uint32_t)ifmtu) { + logfunc("%s: advertised MTU %d" + " is greater than link MTU %d", + ifp->name, mtu.nd_opt_mtu_mtu, ifmtu); + rap->mtu = (uint32_t)ifmtu; + } else + rap->mtu = mtu.nd_opt_mtu_mtu; break; - case ND_OPT_RDNSS: if (len < sizeof(rdnss)) { - logerrx("%s: short RDNSS option", ifp->name); + logfunc("%s: short RDNSS option", ifp->name); break; } memcpy(&rdnss, p, sizeof(rdnss)); |