| #!/usr/bin/env python |
| # |
| # solisten Trace TCP listen events |
| # For Linux, uses BCC, eBPF. Embedded C. |
| # |
| # USAGE: solisten.py [-h] [-p PID] [--show-netns] |
| # |
| # This is provided as a basic example of TCP connection & socket tracing. |
| # It could be useful in scenarios where load balancers needs to be updated |
| # dynamically as application is fully initialized. |
| # |
| # All IPv4 listen attempts are traced, even if they ultimately fail or the |
| # the listening program is not willing to accept(). |
| # |
| # Copyright (c) 2016 Jean-Tiare Le Bigot. |
| # Licensed under the Apache License, Version 2.0 (the "License") |
| # |
| # 04-Mar-2016 Jean-Tiare Le Bigot Created this. |
| |
| import os |
| from socket import inet_ntop, AF_INET, AF_INET6, SOCK_STREAM, SOCK_DGRAM |
| from struct import pack |
| import argparse |
| from bcc import BPF |
| import ctypes as ct |
| |
| # Arguments |
| examples = """Examples: |
| ./solisten.py # Stream socket listen |
| ./solisten.py -p 1234 # Stream socket listen for specified PID only |
| ./solisten.py --netns 4242 # " for the specified network namespace ID only |
| ./solisten.py --show-netns # Show network ns ID (useful for containers) |
| """ |
| |
| parser = argparse.ArgumentParser( |
| description="Stream sockets listen", |
| formatter_class=argparse.RawDescriptionHelpFormatter, |
| epilog=examples) |
| parser.add_argument("--show-netns", action="store_true", |
| help="show network namespace") |
| parser.add_argument("-p", "--pid", default=0, type=int, |
| help="trace this PID only") |
| parser.add_argument("-n", "--netns", default=0, type=int, |
| help="trace this Network Namespace only") |
| parser.add_argument("--ebpf", action="store_true", |
| help=argparse.SUPPRESS) |
| |
| |
| # BPF Program |
| bpf_text = """ |
| #include <net/net_namespace.h> |
| #include <bcc/proto.h> |
| #pragma clang diagnostic push |
| #pragma clang diagnostic ignored "-Wenum-conversion" |
| #include <net/inet_sock.h> |
| #pragma clang diagnostic pop |
| |
| // Common structure for UDP/TCP IPv4/IPv6 |
| struct listen_evt_t { |
| u64 ts_us; |
| u64 pid_tgid; |
| u64 backlog; |
| u64 netns; |
| u64 proto; // familiy << 16 | type |
| u64 lport; // use only 16 bits |
| u64 laddr[2]; // IPv4: store in laddr[0] |
| char task[TASK_COMM_LEN]; |
| }; |
| BPF_PERF_OUTPUT(listen_evt); |
| |
| // Send an event for each IPv4 listen with PID, bound address and port |
| int kprobe__inet_listen(struct pt_regs *ctx, struct socket *sock, int backlog) |
| { |
| // cast types. Intermediate cast not needed, kept for readability |
| struct sock *sk = sock->sk; |
| struct inet_sock *inet = (struct inet_sock *)sk; |
| |
| // Built event for userland |
| struct listen_evt_t evt = { |
| .ts_us = bpf_ktime_get_ns() / 1000, |
| .backlog = backlog, |
| }; |
| |
| // Get process comm. Needs LLVM >= 3.7.1 |
| // see https://github.com/iovisor/bcc/issues/393 |
| bpf_get_current_comm(evt.task, TASK_COMM_LEN); |
| |
| // Get socket IP family |
| u16 family = sk->__sk_common.skc_family; |
| evt.proto = family << 16 | SOCK_STREAM; |
| |
| // Get PID |
| evt.pid_tgid = bpf_get_current_pid_tgid(); |
| |
| ##FILTER_PID## |
| |
| // Get port |
| evt.lport = inet->inet_sport; |
| evt.lport = ntohs(evt.lport); |
| |
| // Get network namespace id, if kernel supports it |
| #ifdef CONFIG_NET_NS |
| evt.netns = sk->__sk_common.skc_net.net->ns.inum; |
| #else |
| evt.netns = 0; |
| #endif |
| |
| ##FILTER_NETNS## |
| |
| // Get IP |
| if (family == AF_INET) { |
| evt.laddr[0] = inet->inet_rcv_saddr; |
| } else if (family == AF_INET6) { |
| bpf_probe_read(evt.laddr, sizeof(evt.laddr), |
| sk->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32); |
| } |
| |
| // Send event to userland |
| listen_evt.perf_submit(ctx, &evt, sizeof(evt)); |
| |
| return 0; |
| }; |
| """ |
| |
| # event data |
| TASK_COMM_LEN = 16 # linux/sched.h |
| class ListenEvt(ct.Structure): |
| _fields_ = [ |
| ("ts_us", ct.c_ulonglong), |
| ("pid_tgid", ct.c_ulonglong), |
| ("backlog", ct.c_ulonglong), |
| ("netns", ct.c_ulonglong), |
| ("proto", ct.c_ulonglong), |
| ("lport", ct.c_ulonglong), |
| ("laddr", ct.c_ulonglong * 2), |
| ("task", ct.c_char * TASK_COMM_LEN) |
| ] |
| |
| # TODO: properties to unpack protocol / ip / pid / tgid ... |
| |
| # Format output |
| def event_printer(show_netns): |
| def print_event(cpu, data, size): |
| # Decode event |
| event = ct.cast(data, ct.POINTER(ListenEvt)).contents |
| |
| pid = event.pid_tgid & 0xffffffff |
| proto_family = event.proto & 0xff |
| proto_type = event.proto >> 16 & 0xff |
| |
| if proto_family == SOCK_STREAM: |
| protocol = "TCP" |
| elif proto_family == SOCK_DGRAM: |
| protocol = "UDP" |
| else: |
| protocol = "UNK" |
| |
| address = "" |
| if proto_type == AF_INET: |
| protocol += "v4" |
| address = inet_ntop(AF_INET, pack("I", event.laddr[0])) |
| elif proto_type == AF_INET6: |
| address = inet_ntop(AF_INET6, event.laddr) |
| protocol += "v6" |
| |
| # Display |
| if show_netns: |
| print("%-6d %-12.12s %-12s %-6s %-8s %-5s %-39s" % ( |
| pid, event.task, event.netns, protocol, event.backlog, |
| event.lport, address, |
| )) |
| else: |
| print("%-6d %-12.12s %-6s %-8s %-5s %-39s" % ( |
| pid, event.task, protocol, event.backlog, |
| event.lport, address, |
| )) |
| |
| return print_event |
| |
| if __name__ == "__main__": |
| # Parse arguments |
| args = parser.parse_args() |
| |
| pid_filter = "" |
| netns_filter = "" |
| |
| if args.pid: |
| pid_filter = "if (evt.pid_tgid != %d) return 0;" % args.pid |
| if args.netns: |
| netns_filter = "if (evt.netns != %d) return 0;" % args.netns |
| |
| bpf_text = bpf_text.replace("##FILTER_PID##", pid_filter) |
| bpf_text = bpf_text.replace("##FILTER_NETNS##", netns_filter) |
| |
| if args.ebpf: |
| print(bpf_text) |
| exit() |
| |
| # Initialize BPF |
| b = BPF(text=bpf_text) |
| b["listen_evt"].open_perf_buffer(event_printer(args.show_netns)) |
| |
| # Print headers |
| if args.show_netns: |
| print("%-6s %-12s %-12s %-6s %-8s %-5s %-39s" % |
| ("PID", "COMM", "NETNS", "PROTO", "BACKLOG", "PORT", "ADDR")) |
| else: |
| print("%-6s %-12s %-6s %-8s %-5s %-39s" % |
| ("PID", "COMM", "PROTO", "BACKLOG", "PORT", "ADDR")) |
| |
| # Read events |
| while 1: |
| b.perf_buffer_poll() |