diff options
| -rw-r--r-- | README.md | 11 | ||||
| -rw-r--r-- | mtu1280d.c | 5 |
2 files changed, 9 insertions, 7 deletions
@@ -21,10 +21,13 @@ large packets destined to the desired IP to the netfilter queue. Example rules: ``` -iptables -t mangle -A PREROUTING -d 2001:470:1f04:d63::2/128 -m length --length 1281:65535 -j -NFQUEUE --queue-num 1280 -iptables -A INPUT -m mark --mark 0x501 -m comment --comment "Drop packets marked 1281 (too big)" -j DROP +iptables -t mangle -A PREROUTING -d 2001:db1::1280/128 -j -NFQUEUE --queue-num 1280 ``` +mtu1280d will, when it sees a packet > 1280 bytes long, +both reject the packet as well as generate an ICMPv6 Packet Too Big +back to the sender. + REQUIREMENTS ------------ @@ -60,7 +63,7 @@ ip6tables-restore /etc/iptables/rules.v6 :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] --A PREROUTING -d 2001:470:1:18::1280/128 -m length --length 1:65535 -m comment --comment "Mark packets using mtu1280d as small enough (1280) or too big (1281)" -j NFQUEUE --queue-num 1280 +-A PREROUTING -d 2001:db8::1280/128 -j NFQUEUE --queue-num 1280 COMMIT # Completed on Wed Feb 18 10:14:54 2015 # Generated by ip6tables-save v1.4.21 on Wed Feb 18 10:14:54 2015 @@ -69,8 +72,6 @@ COMMIT :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :CHECK_ABUSE - [0:0] -:ONLY-GIGO - [0:0] --A INPUT -m mark --mark 0x501 -m comment --comment "Drop packets marked 1281 (too big)" -j DROP COMMIT # Completed on Wed Feb 18 10:14:54 2015 ``` @@ -396,10 +396,11 @@ cb (struct nfq_q_handle *qh, struct nfgenmsg *nfmsg, } } mark = block_pkt (nfa); + int v = (mark == 1280) ? NF_ACCEPT : NF_DROP; if (do_debug) { - printf("\nnfq_set_verdict2(qh, id=%d, v=NF_ACCEPT, mark=%d, 0, NULL)\n",id,mark); + printf("\nnfq_set_verdict2(qh, id=%d, v=%d, mark=%d, 0, NULL)\n",id,v,mark); } - return nfq_set_verdict2 (qh, id, NF_ACCEPT, mark, 0, NULL); + return nfq_set_verdict2 (qh, id, v, mark, 0, NULL); } |