diff options
Diffstat (limited to 'src/plugins/nat/nat_inlines.h')
| -rw-r--r-- | src/plugins/nat/nat_inlines.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/plugins/nat/nat_inlines.h b/src/plugins/nat/nat_inlines.h index adfb1d51954..8922c05c393 100644 --- a/src/plugins/nat/nat_inlines.h +++ b/src/plugins/nat/nat_inlines.h @@ -328,6 +328,54 @@ make_sm_kv (clib_bihash_kv_8_8_t * kv, ip4_address_t * addr, u8 proto, kv->value = ~0ULL; } +always_inline void +mss_clamping (snat_main_t * sm, tcp_header_t * tcp, ip_csum_t * sum) +{ + u8 *data; + u8 opt_len, opts_len, kind; + u16 mss; + + if (!(sm->mss_clamping && tcp_syn (tcp))) + return; + + opts_len = (tcp_doff (tcp) << 2) - sizeof (tcp_header_t); + data = (u8 *) (tcp + 1); + for (; opts_len > 0; opts_len -= opt_len, data += opt_len) + { + kind = data[0]; + + if (kind == TCP_OPTION_EOL) + break; + else if (kind == TCP_OPTION_NOOP) + { + opt_len = 1; + continue; + } + else + { + if (opts_len < 2) + return; + opt_len = data[1]; + + if (opt_len < 2 || opt_len > opts_len) + return; + } + + if (kind == TCP_OPTION_MSS) + { + mss = *(u16 *) (data + 2); + if (clib_net_to_host_u16 (mss) > sm->mss_clamping) + { + *sum = + ip_csum_update (*sum, mss, sm->mss_value_net, ip4_header_t, + length); + clib_memcpy (data + 2, &sm->mss_value_net, 2); + } + return; + } + } +} + #endif /* __included_nat_inlines_h__ */ /* |