iptables: enable TCP matching with "-m tcp".

A couple other things that changed:

- There's a proper extension registration system for matchers. Anyone
  adding another matcher can use tcp_matcher.go or udp_matcher.go as a
  template.
- All logging and use of syserr.Error in the netfilter package happens at the
  highest possible level (public functions). Lower-level functions just
  return normal, descriptive golang errors.

1 files changed, 0 insertions, 1 deletions

diff --git a/pkg/tcpip/iptables/BUILD b/pkg/tcpip/iptables/BUILD
index bab26580b..d1b73cfdf 100644
--- a/pkg/tcpip/iptables/BUILD
+++ b/pkg/tcpip/iptables/BUILD
@@ -8,7 +8,6 @@ go_library(
         "iptables.go",
         "targets.go",
         "types.go",
-        "udp_matcher.go",
     ],
     visibility = ["//visibility:public"],
     deps = [