diff options
| -rw-r--r-- | doc/payload-expression.txt | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/doc/payload-expression.txt b/doc/payload-expression.txt index 351c79bc..8b538968 100644 --- a/doc/payload-expression.txt +++ b/doc/payload-expression.txt @@ -134,13 +134,12 @@ Destination address | ipv4_addr |====================== -Careful with matching on *ip length*: If GRO/GSO is enabled, then the Linux -kernel might aggregate several packets into one big packet that is larger than -MTU. Moreover, if GRO/GSO maximum size is larger than 65535 (see man ip-link(8), -specifically gro_ipv6_max_size and gso_ipv6_max_size), then *ip length* might -be 0 for such jumbo packets. *meta length* allows you to match on the packet -length including the IP header size. If you want to perform heuristics on the -*ip length* field, then disable GRO/GSO. +Careful with matching on *ip length*: The Linux kernel might aggregate several +packets into one big packet that is larger than MTU. Moreover, if GRO/GSO +maximum size is larger than 65535 (see man ip-link(8), specifically +gro_ipv4_max_size and gso_ipv4_max_size), then *ip length* might be 0 for such +jumbo packets. *meta length* allows you to match on the packet length including +the IP header size. ICMP HEADER EXPRESSION ~~~~~~~~~~~~~~~~~~~~~~ @@ -252,13 +251,12 @@ Destination address | ipv6_addr |======================= -Careful with matching on *ip6 length*: If GRO/GSO is enabled, then the Linux -kernel might aggregate several packets into one big packet that is larger than -MTU. Moreover, if GRO/GSO maximum size is larger than 65535 (see man ip-link(8), -specifically gro_ipv6_max_size and gso_ipv6_max_size), then *ip6 length* might -be 0 for such jumbo packets. *meta length* allows you to match on the packet -length including the IP header size. If you want to perform heuristics on the -*ip6 length* field, then disable GRO/GSO. +Careful with matching on *ip6 length*: The Linux kernel might aggregate several +packets into one big packet that is larger than MTU. Moreover, if GRO/GSO +maximum size is larger than 65535 (see man ip-link(8), specifically +gro_max_size and gso_max_size), then *ip6 length* might be 0 for such +jumbo packets. *meta length* allows you to match on the packet length including +the IPv6 header size. .Using ip6 header expressions ----------------------------- |