diff options
Diffstat (limited to 'doc/developer')
| -rw-r--r-- | doc/developer/tracing.rst | 72 | ||||
| -rw-r--r-- | doc/developer/workflow.rst | 2 |
2 files changed, 73 insertions, 1 deletions
diff --git a/doc/developer/tracing.rst b/doc/developer/tracing.rst index c194ae1270..71f7b4ac49 100644 --- a/doc/developer/tracing.rst +++ b/doc/developer/tracing.rst @@ -173,6 +173,78 @@ Example:: When using LTTng, you can also get zlogs as trace events by enabling the ``lttng_ust_tracelog:*`` event class. +To see available SystemTap USDT probes, run:: + + stap -L 'process("/usr/lib/frr/bgpd").mark("*")' + +Example:: + + root@host ~> stap -L 'process("/usr/lib/frr/bgpd").mark("*")' + process("/usr/lib/frr/bgpd").mark("capability_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("input_filter") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long + process("/usr/lib/frr/bgpd").mark("keepalive_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("notification_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("open_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("output_filter") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long + process("/usr/lib/frr/bgpd").mark("packet_read") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("process_update") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long $arg6:long + process("/usr/lib/frr/bgpd").mark("refresh_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("update_process") $arg1:long $arg2:long + +When using SystemTap, you can also easily attach to an existing function:: + + stap -L 'process("/usr/lib/frr/bgpd").function("bgp_update_receive")' + +Example:: + + root@host ~> stap -L 'process("/usr/lib/frr/bgpd").function("bgp_update_receive")' + process("/usr/lib/frr/bgpd").function("bgp_update_receive@bgpd/bgp_packet.c:1531") $peer:struct peer* $size:bgp_size_t $attr:struct attr $restart:_Bool $nlris:struct bgp_nlri[] $__func__:char const[] const + +Complete ``bgp.stp`` example using SystemTap to show BGP peer, prefix and aspath +using ``process_update`` USDT:: + + global pkt_size; + probe begin + { + ansi_clear_screen(); + println("Starting..."); + } + probe process("/usr/lib/frr/bgpd").function("bgp_update_receive") + { + pkt_size <<< $size; + } + probe process("/usr/lib/frr/bgpd").mark("process_update") + { + aspath = @cast($arg6, "attr")->aspath; + printf("> %s via %s (%s)\n", + user_string($arg2), + user_string(@cast($arg1, "peer")->host), + user_string(@cast(aspath, "aspath")->str)); + } + probe end + { + if (@count(pkt_size)) + print(@hist_linear(pkt_size, 0, 20, 2)); + } + +Output:: + + Starting... + > 192.168.0.0/24 via 192.168.0.1 (65534) + > 192.168.100.1/32 via 192.168.0.1 (65534) + > 172.16.16.1/32 via 192.168.0.1 (65534 65030) + ^Cvalue |-------------------------------------------------- count + 0 | 0 + 2 | 0 + 4 |@ 1 + 6 | 0 + 8 | 0 + ~ + 18 | 0 + 20 | 0 + >20 |@@@@@ 5 + + Concepts -------- diff --git a/doc/developer/workflow.rst b/doc/developer/workflow.rst index 41f56e3a03..abdbea5a9c 100644 --- a/doc/developer/workflow.rst +++ b/doc/developer/workflow.rst @@ -563,7 +563,7 @@ In general, code submitted into FRR will be rejected if it uses unsafe programming practices. While there is no enforced overall ruleset, the following requirements have achieved consensus: -- ``strcpy``, ``strcat`` and ``sprintf`` are inacceptable without exception. +- ``strcpy``, ``strcat`` and ``sprintf`` are unacceptable without exception. Use ``strlcpy``, ``strlcat`` and ``snprintf`` instead. (Rationale: even if you know the operation cannot overflow the buffer, a future code change may inadvertedly introduce an overflow.) |