From 6310bef51148b747f9019bd0bd67fd285eff0ae3 Mon Sep 17 00:00:00 2001 From: "Thierry Fournier / OZON.IO" Date: Sun, 24 Jul 2016 20:16:50 +0200 Subject: [PATCH] MINOR: tcp: Return TCP statistics like RTT and RTT variance This patch adds 4 new sample fetches which returns the RTT of the established connexion and the RTT variance. The established connection can be between the client and HAProxy, and between HAProxy and the server. This is very useful for statistics. A great use case is the estimation of the TCP connection time of the client. Note that the RTT of the server side is not so interesting because we already have the connect() time. --- doc/configuration.txt | 17 ++++++++- src/proto_tcp.c | 82 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 98 insertions(+), 1 deletion(-) diff --git a/doc/configuration.txt b/doc/configuration.txt index 2a1782ad45..fc98e5c5d7 100644 --- a/doc/configuration.txt +++ b/doc/configuration.txt @@ -12737,6 +12737,22 @@ dst_port : integer a same server, or to pass the destination port information to a server using an HTTP header. +fc_rtt() : integer + Returns the Round Trip Time (RTT) measured by the kernel for the client + connection. is facultative, by default the unit is milliseconds. + can be set to "ms" for milliseconds or "us" for microseconds. If the server + connection is not established, if the connection is not TCP or if the + operating system does not support TCP_INFO, for example Linux kernels before + 2.4, the sample fetch fails. + +fc_rttvar() : integer + Returns the Round Trip Time (RTT) variance measured by the kernel for the + client connection. is facultative, by default the unit is milliseconds. + can be set to "ms" for milliseconds or "us" for microseconds. If the + server connection is not established, if the connection is not TCP or if the + operating system does not support TCP_INFO, for example Linux kernels before + 2.4, the sample fetch fails. + fe_id : integer Returns an integer containing the current frontend's id. It can be used in backends to check from which backend it was called, or to stick all users @@ -13117,7 +13133,6 @@ srv_id : integer While it's almost only used with ACLs, it may be used for logging or debugging. - 7.3.4. Fetching samples at Layer 5 ---------------------------------- diff --git a/src/proto_tcp.c b/src/proto_tcp.c index 83bdff8789..4f6b3c3e15 100644 --- a/src/proto_tcp.c +++ b/src/proto_tcp.c @@ -2313,6 +2313,84 @@ smp_fetch_dport(const struct arg *args, struct sample *smp, const char *kw, void return 1; } +#ifdef TCP_INFO + +/* Returns some tcp_info data is its avalaible. "dir" must be set to 0 if + * the client connection is require, otherwise it is set to 1. "val" represents + * the required value. Use 0 for rtt and 1 for rttavg. "unit" is the expected unit + * by default, the rtt is in us. Id "unit" is set to 0, the unit is us, if it is + * set to 1, the untis are milliseconds. + * If the function fails it returns 0, otherwise it returns 1 and "result" is filled. + */ +static inline int get_tcp_info(const struct arg *args, struct sample *smp, + int dir, int val) +{ + struct connection *conn; + struct tcp_info info; + socklen_t optlen; + + /* strm can be null. */ + if (!smp->strm) + return 0; + + /* get the object associated with the stream interface.The + * object can be other thing than a connection. For example, + * it be a appctx. */ + conn = objt_conn(smp->strm->si[dir].end); + if (!conn) + return 0; + + /* The fd may not be avalaible for the tcp_info struct, and the + syscal can fail. */ + optlen = sizeof(info); + if (getsockopt(conn->t.sock.fd, SOL_TCP, TCP_INFO, &info, &optlen) == -1) + return 0; + + /* extract the value. */ + smp->data.type = SMP_T_SINT; + switch (val) { + case 0: smp->data.u.sint = info.tcpi_rtt; break; + case 1: smp->data.u.sint = info.tcpi_rttvar; break; + default: return 0; + } + + /* Convert the value as expected. */ + if (args) { + if (args[0].type == ARGT_STR) { + if (strcmp(args[0].data.str.str, "us") == 0) { + /* Do nothing. */ + } else if (strcmp(args[0].data.str.str, "ms") == 0) { + smp->data.u.sint = (smp->data.u.sint + 500) / 1000; + } else + return 0; + } else if (args[0].type == ARGT_STOP) { + smp->data.u.sint = (smp->data.u.sint + 500) / 1000; + } else + return 0; + } + + return 1; +} + +/* get the mean rtt of a client connexion */ +static int +smp_fetch_fc_rtt(const struct arg *args, struct sample *smp, const char *kw, void *private) +{ + if (!get_tcp_info(args, smp, 0, 0)) + return 0; + return 1; +} + +/* get the variance of the mean rtt of a client connexion */ +static int +smp_fetch_fc_rttvar(const struct arg *args, struct sample *smp, const char *kw, void *private) +{ + if (!get_tcp_info(args, smp, 0, 1)) + return 0; + return 1; +} +#endif + #ifdef IPV6_V6ONLY /* parse the "v4v6" bind keyword */ static int bind_parse_v4v6(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err) @@ -2540,6 +2618,10 @@ static struct sample_fetch_kw_list sample_fetch_keywords = {ILH, { { "dst_port", smp_fetch_dport, 0, NULL, SMP_T_SINT, SMP_USE_L4CLI }, { "src", smp_fetch_src, 0, NULL, SMP_T_IPV4, SMP_USE_L4CLI }, { "src_port", smp_fetch_sport, 0, NULL, SMP_T_SINT, SMP_USE_L4CLI }, +#ifdef TCP_INFO + { "fc_rtt", smp_fetch_fc_rtt, ARG1(0,STR), NULL, SMP_T_SINT, SMP_USE_L4CLI }, + { "fc_rttvar", smp_fetch_fc_rttvar, ARG1(0,STR), NULL, SMP_T_SINT, SMP_USE_L4CLI }, +#endif { /* END */ }, }}; -- 2.39.5