name : sock-parse-http.lua #!/usr/bin/env bcc-lua --[[ Copyright 2016 Marek Vavrusa <mvavrusa@cloudflare.com> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ]] -- Simple parsing example of TCP/HTTP that counts frequency of types of requests -- and shows more complicated pattern matching constructions and slices. -- Rewrite of a BCC example: -- https://github.com/iovisor/bcc/blob/master/examples/networking/http_filter/http-parse-simple.c local ffi = require("ffi") local bpf = require("bpf") local S = require("syscall") -- Shared part of the program local map = bpf.map('hash', 64) -- Kernel-space part of the program local prog = bpf.socket('lo', function (skb) -- Only ingress so we don't count twice on loopback if skb.ingress_ifindex == 0 then return end local data = pkt.ip.tcp.data -- Get TCP protocol dissector -- Continue only if we have 7 bytes of TCP data if data + 7 > skb.len then return end -- Fetch 4 bytes of TCP data and compare local h = data(0, 4) if h == 'HTTP' or h == 'GET ' or h == 'POST' or h == 'PUT ' or h == 'HEAD' or h == 'DELE' then -- If hash key doesn't exist, create it -- otherwise increment counter local v = map[h] if not v then map[h] = 1 else xadd(map[h], 1) end end end) -- User-space part of the program for _ = 1, 10 do local strkey = ffi.new('uint32_t [1]') local s = '' for k,v in map.pairs,map,0 do strkey[0] = bpf.ntoh(k) s = s..string.format('%s %d ', ffi.string(strkey, 4):match '^%s*(.-)%s*$', tonumber(v)) end if #s > 0 then print(s..'messages') end S.sleep(1) end