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ptcpdump

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ptcpdump is an eBPF-based implementation of tcpdump that includes an additional feature: it adds process information as comments for each packet when available. Inspired by jschwinger233/skbdump.

Table of Contents

• Features
• Installation
  • Requirements
• Usage
  • Example commands
  • Example output
  • Running with Docker
  • Backend
  • Flags
• Compare with tcpdump
• Developing
  • Dependencies
  • Building

Features

• Process-aware
  • Aware of the process information associated with the packets.
  • Supports filtering packets by process ID and process name.
• Container-aware and Kubernetes-aware
  • Aware of the container and pod information associated with the packets.
  • Supports multiple container runtimes: Docker Engine and containerd
  • Supports filtering packets by container ID, container name and pod name.
• Supports using pcap-filter(7) syntax for filtering packets.
• Directly applies filters in the kernel space.
• Supports saving captured packets in the PcapNG format for offline analysis with third-party tools such as Wireshark/tshark/tcpdump.
• Supports packet capture for network interfaces under the specified network namespace.

Installation

You can download the statically linked executable for x86_64 and arm64 from the releases page.

Requirements

Linux kernel >= 5.2 (compiled with BPF and BTF support).

Usage

Example commands

Filter like tcpdump:

sudo ptcpdump -i eth0 tcp
sudo ptcpdump -i eth0 -A -s 0 -n -v tcp and port 80 and host 10.10.1.1
sudo ptcpdump -i eth0 'tcp[tcpflags] & (tcp-syn|tcp-fin) != 0'

Multiple interfaces:

sudo ptcpdump -i eth0 -i lo

Filter by process:

sudo ptcpdump -i any --pid 1234 --pid 233 -f
sudo ptcpdump -i any --pname curl

Capture by process via run target program:

sudo ptcpdump -i any -- curl ubuntu.com

Filter by container:

sudo ptcpdump -i any --container-id 36f0310403b1
sudo ptcpdump -i any --container-name test

Filter by Pod:

sudo ptcpdump -i any --pod-name test.default

Save data in PcapNG format:

sudo ptcpdump -i any -w demo.pcapng
sudo ptcpdump -i any -w - port 80 | tcpdump -n -r -
sudo ptcpdump -i any -w - port 80 | tshark -r -

Capturing interfaces in other network namespaces:

sudo ptcpdump -i lo --netns /run/netns/foo --netns /run/netns/bar
sudo ptcpdump -i any --netns /run/netns/foobar
sudo ptcpdump -i any --netns /proc/26/ns/net

Example output

Default:

09:32:09.718892 vethee2a302f wget.3553008 In IP 10.244.0.2.33426 > 139.178.84.217.80: Flags [S], seq 4113492822, win 64240, length 0, ParentProc [python3.834381], Container [test], Pod [test.default]
09:32:09.718941 eth0 wget.3553008 Out IP 172.19.0.2.33426 > 139.178.84.217.80: Flags [S], seq 4113492822, win 64240, length 0, ParentProc [python3.834381], Container [test], Pod [test.default]

With -q:

09:32:09.718892 vethee2a302f wget.3553008 In IP 10.244.0.2.33426 > 139.178.84.217.80: tcp 0, ParentProc [python3.834381], Container [test], Pod [test.default]
09:32:09.718941 eth0 wget.3553008 Out IP 172.19.0.2.33426 > 139.178.84.217.80: tcp 0, ParentProc [python3.834381], Container [test], Pod [test.default]

With -v:

13:44:41.529003 eth0 In IP (tos 0x4, ttl 45, id 45428, offset 0, flags [DF], proto TCP (6), length 52)
    139.178.84.217.443 > 172.19.0.2.42606: Flags [.], cksum 0x5284, seq 3173118145, ack 1385712707, win 118, options [nop,nop,TS val 134560683 ecr 1627716996], length 0
    Process (pid 553587, cmd /usr/bin/wget, args wget kernel.org)
    ParentProc (pid 553296, cmd /bin/sh, args sh)
    Container (name test, id d9028334568bf75a5a084963a8f98f78c56bba7f45f823b3780a135b71b91e95, image docker.io/library/alpine:3.18, labels {"io.cri-containerd.kind":"container","io.kubernetes.container.name":"test","io.kubernetes.pod.name":"test","io.kubernetes.pod.namespace":"default","io.kubernetes.pod.uid":"9e4bc54b-de48-4b1c-8b9e-54709f67ed0c"})
    Pod (name test, namespace default, UID 9e4bc54b-de48-4b1c-8b9e-54709f67ed0c, labels {"run":"test"}, annotations {"kubernetes.io/config.seen":"2024-07-21T12:41:00.460249620Z","kubernetes.io/config.source":"api"})

Using --context to limit context to include in the output:

# --context=process
09:32:09.718892 vethee2a302f wget.3553008 In IP 10.244.0.2.33426 > 139.178.84.217.80: Flags [S], seq 4113492822, win 64240, length 0

# -v --context=process
13:44:41.529003 eth0 In IP (tos 0x4, ttl 45, id 45428, offset 0, flags [DF], proto TCP (6), length 52)
    139.178.84.217.443 > 172.19.0.2.42606: Flags [.], cksum 0x5284, seq 3173118145, ack 1385712707, win 118, options [nop,nop,TS val 134560683 ecr 1627716996], length 0
    Process (pid 553587, cmd /usr/bin/wget, args wget kernel.org)

# -v --context=process,parentproc,container,pod
# or -v --context=process --context=parentproc --context=container --context=pod
13:44:41.529003 eth0 In IP (tos 0x4, ttl 45, id 45428, offset 0, flags [DF], proto TCP (6), length 52)
    139.178.84.217.443 > 172.19.0.2.42606: Flags [.], cksum 0x5284, seq 3173118145, ack 1385712707, win 118, options [nop,nop,TS val 134560683 ecr 1627716996], length 0
    Process (pid 553587, cmd /usr/bin/wget, args wget kernel.org)
    ParentProc (pid 553296, cmd /bin/sh, args sh)
    Container (name test, id d9028334568bf75a5a084963a8f98f78c56bba7f45f823b3780a135b71b91e95, image docker.io/library/alpine:3.18, labels {"io.cri-containerd.kind":"container","io.kubernetes.container.name":"test","io.kubernetes.pod.name":"test","io.kubernetes.pod.namespace":"default","io.kubernetes.pod.uid":"9e4bc54b-de48-4b1c-8b9e-54709f67ed0c"})
    Pod (name test, namespace default, UID 9e4bc54b-de48-4b1c-8b9e-54709f67ed0c, labels {"run":"test"}, annotations {"kubernetes.io/config.seen":"2024-07-21T12:41:00.460249620Z","kubernetes.io/config.source":"api"})

With -A:

14:44:34.457504 ens33 curl.205562 Out IP 10.0.2.15.39984 > 139.178.84.217.80: Flags [P.], seq 2722472188:2722472262, ack 892036871, win 64240, length 74, ParentProc [bash.180205]
E..r.,@.@.o.
.....T..0.P.E..5+g.P.......GET / HTTP/1.1
Host: kernel.org
User-Agent: curl/7.81.0
Accept: */*

With -x:

14:44:34.457504 ens33 curl.205562 Out IP 10.0.2.15.39984 > 139.178.84.217.80: Flags [P.], seq 2722472188:2722472262, ack 892036871, win 64240, length 74, ParentProc [bash.180205]
        0x0000:  4500 0072 de2c 4000 4006 6fbf 0a00 020f
        0x0010:  8bb2 54d9 9c30 0050 a245 a0fc 352b 6707
        0x0020:  5018 faf0 ecfe 0000 4745 5420 2f20 4854
        0x0030:  5450 2f31 2e31 0d0a 486f 7374 3a20 6b65
        0x0040:  726e 656c 2e6f 7267 0d0a 5573 6572 2d41
        0x0050:  6765 6e74 3a20 6375 726c 2f37 2e38 312e
        0x0060:  300d 0a41 6363 6570 743a 202a 2f2a 0d0a
        0x0070:  0d0a

With -X:

14:44:34.457504 ens33 curl.205562 Out IP 10.0.2.15.39984 > 139.178.84.217.80: Flags [P.], seq 2722472188:2722472262, ack 892036871, win 64240, length 74, ParentProc [bash.180205]
        0x0000:  4500 0072 de2c 4000 4006 6fbf 0a00 020f  E..r.,@.@.o.....
        0x0010:  8bb2 54d9 9c30 0050 a245 a0fc 352b 6707  ..T..0.P.E..5+g.
        0x0020:  5018 faf0 ecfe 0000 4745 5420 2f20 4854  P.......GET / HT
        0x0030:  5450 2f31 2e31 0d0a 486f 7374 3a20 6b65  TP/1.1..Host: ke
        0x0040:  726e 656c 2e6f 7267 0d0a 5573 6572 2d41  rnel.org..User-A
        0x0050:  6765 6e74 3a20 6375 726c 2f37 2e38 312e  gent: curl/7.81.
        0x0060:  300d 0a41 6363 6570 743a 202a 2f2a 0d0a  0..Accept: */*..
        0x0070:  0d0a                                     ..

Running with Docker

Docker images for ptcpdump are published at https://quay.io/repository/ptcpdump/ptcpdump.

docker run --privileged --rm -t --net=host --pid=host \
  -v /sys/fs/cgroup:/sys/fs/cgroup:ro \
  quay.io/ptcpdump/ptcpdump:latest ptcpdump -i any -c 2 tcp

Backend

ptcpdump supports specifying a particular eBPF technology for packet capture through the --backend flag.

If this flag isn't specified, it defaults to tc.

Flags

Usage:
  ptcpdump [flags] [expression] [-- command [args]]

Examples:
  sudo ptcpdump -i any tcp
  sudo ptcpdump -i eth0 -i lo
  sudo ptcpdump -i eth0 --pid 1234 port 80 and host 10.10.1.1
  sudo ptcpdump -i any --pname curl -A
  sudo ptcpdump -i any --container-id 36f0310403b1
  sudo ptcpdump -i any --container-name test
  sudo ptcpdump -i any -- curl ubuntu.com
  sudo ptcpdump -i any -w ptcpdump.pcapng
  sudo ptcpdump -i any -w - | tcpdump -n -r -
  sudo ptcpdump -i any -w - | tshark -r -
  ptcpdump -r ptcpdump.pcapng

Expression: see "man 7 pcap-filter"

Flags:
      --backend string                               Specify the backend to use for capturing packets. Possible values are "tc" and "cgroup-skb" (default "tc")
      --container-id string                          Filter by container id (only TCP and UDP packets are supported)
      --container-name string                        Filter by container name (only TCP and UDP packets are supported)
      --containerd-address string                    Address of containerd service (default "/run/containerd/containerd.sock")
      --context strings                              Specify which context information to include in the output (default [process,parentproc,container,pod])
      --count                                        Print only on stdout the packet count when reading capture file instead of parsing/printing the packets
      --cri-runtime-address string                   Address of CRI container runtime service (default: uses in order the first successful one of [/var/run/dockershim.sock, /var/run/cri-dockerd.sock, /run/crio/crio.sock, /run/containerd/containerd.sock])
      --delay-before-handle-packet-events duration   Delay some durations before handle packet events
  -Q, --direction string                             Choose send/receive direction for which packets should be captured. Possible values are 'in', 'out' and 'inout' (default "inout")
      --docker-address string                        Address of Docker Engine service (default "/var/run/docker.sock")
      --embed-keylog-to-pcapng -- CMD [ARGS]         Write TLS Key Log file to this path (experimental: only support unstripped Go binary and must combined with -- CMD [ARGS])
      --event-chan-size uint                         Size of event chan (default 20)
      --exec-events-worker-number uint               Number of worker to handle exec events (default 50)
  -f, --follow-forks                                 Trace child processes as they are created by currently traced processes when filter by process
  -h, --help                                         help for ptcpdump
  -i, --interface strings                            Interfaces to capture (default [lo])
      --kernel-btf string                            specify kernel BTF file (default: uses in order the first successful one of [/sys/kernel/btf/vmlinux, /var/lib/ptcpdump/btf/vmlinux, /var/lib/ptcpdump/btf/vmlinux-$(uname -r), /var/lib/ptcpdump/btf/$(uname -r).btf, download BTF file from https://mirrors.openanolis.cn/coolbpf/btf/ and https://github.com/aquasecurity/btfhub-archive/]
  -D, --list-interfaces                              Print the list of the network interfaces available on the system
      --log-level string                             Set the logging level ("debug", "info", "warn", "error", "fatal") (default "warn")
      --micro                                        Shorthands for --time-stamp-precision=micro
      --nano                                         Shorthands for --time-stamp-precision=nano
      --netns strings                                Path to an network namespace file or name (default [/proc/self/ns/net])
  -n, --no-convert-addr count                        Don't convert addresses (i.e., host addresses, port numbers, etc.) to names
  -t, --no-timestamp                                 Don't print a timestamp on each dump line
  -#, --number                                       Print an optional packet number at the beginning of the line
      --oneline                                      Print parsed packet output in a single line
      --pid uints                                    Filter by process IDs (only TCP and UDP packets are supported) (default [])
      --pname string                                 Filter by process name (only TCP and UDP packets are supported)
      --pod-name string                              Filter by pod name (format: NAME.NAMESPACE, only TCP and UDP packets are supported)
      --print                                        Print parsed packet output, even if the raw packets are being saved to a file with the -w flag
  -A, --print-data-in-ascii                          Print each packet (minus its link level header) in ASCII
  -x, --print-data-in-hex count                      When parsing and printing, in addition to printing the headers of each packet, print the data of each packet in hex
  -X, --print-data-in-hex-ascii count                When parsing and printing, in addition to printing the headers of each packet, print the data of each packet in hex and ASCII
  -q, --quiet                                        Quiet output. Print less protocol information so output lines are shorter
  -r, --read-file string                             Read packets from file (which was created with the -w option). e.g. ptcpdump.pcapng
  -c, --receive-count uint                           Exit after receiving count packets
  -s, --snapshot-length uint32                       Snarf snaplen bytes of data from each packet rather than the default of 262144 bytes (default 262144)
      --time-stamp-precision string                  When capturing, set the time stamp precision for the capture to the format (default "micro")
  -v, --verbose count                                When parsing and printing, produce (slightly more) verbose output
      --version                                      Print the ptcpdump and libpcap version strings and exit
  -w, --write-file string                            Write the raw packets to file rather than parsing and printing them out. They can later be printed with the -r option. Standard output is used if file is '-'. e.g. ptcpdump.pcapng
      --write-keylog-file -- CMD [ARGS]              Write TLS Key Log file to this path (experimental: only support unstripped Go binary and must combined with -- CMD [ARGS])

Compare with tcpdump

Developing

Dependencies

• Go >= 1.23
• Clang/LLVM >= 14
• Bison >= 3.8
• Lex/Flex >= 2.6
• GCC
• GNU make
• autoconf

Building

1. Build eBPF programs (optional):

   make build-bpf
   

   Or:

   make build-bpf-via-docker
   

2. Build ptcpdump:

   make build
   

   Or:

   make build-via-docker