From ca7f11ebc4d4a99ccfd44be8555d505b26996c12 Mon Sep 17 00:00:00 2001 From: Arjun Roy Date: Mon, 25 Jul 2022 12:49:35 -0400 Subject: [PATCH 2/2] ss: output TCP BBRv3 diag information Add logic for printing diag information for TCP BBRv3 congestion control. This commit leaves in place the support for printing the earlier TCP BBRv1 congestion control information. Both BBRv1 and BBRv3 are using the same enum value. The BBRv3 struct starts with the same data as BBRv1, so it is is backward-compatible with BBRv1, to allow lder ss binaries to print basic information for BBRv3. We use the size of the returned data and the version field to check the version of the data. Signed-off-by: Arjun Roy Signed-off-by: Neal Cardwell Signed-off-by: David Morley --- include/uapi/linux/inet_diag.h | 23 ++++++++++++ misc/ss.c | 66 +++++++++++++++++++++++++++++++++- 2 files changed, 88 insertions(+), 1 deletion(-) --- a/include/uapi/linux/inet_diag.h +++ b/include/uapi/linux/inet_diag.h @@ -229,6 +229,29 @@ struct tcp_bbr_info { __u32 bbr_min_rtt; /* min-filtered RTT in uSec */ __u32 bbr_pacing_gain; /* pacing gain shifted left 8 bits */ __u32 bbr_cwnd_gain; /* cwnd gain shifted left 8 bits */ + __u32 bbr_bw_hi_lsb; /* lower 32 bits of bw_hi */ + __u32 bbr_bw_hi_msb; /* upper 32 bits of bw_hi */ + __u32 bbr_bw_lo_lsb; /* lower 32 bits of bw_lo */ + __u32 bbr_bw_lo_msb; /* upper 32 bits of bw_lo */ + __u8 bbr_mode; /* current bbr_mode in state machine */ + __u8 bbr_phase; /* current state machine phase */ + __u8 unused1; /* alignment padding; not used yet */ + __u8 bbr_version; /* BBR algorithm version */ + __u32 bbr_inflight_lo; /* lower short-term data volume bound */ + __u32 bbr_inflight_hi; /* higher long-term data volume bound */ + __u32 bbr_extra_acked; /* max excess packets ACKed in epoch */ +}; + +/* TCP BBR congestion control bbr_phase as reported in netlink/ss stats. */ +enum tcp_bbr_phase { + BBR_PHASE_INVALID = 0, + BBR_PHASE_STARTUP = 1, + BBR_PHASE_DRAIN = 2, + BBR_PHASE_PROBE_RTT = 3, + BBR_PHASE_PROBE_BW_UP = 4, + BBR_PHASE_PROBE_BW_DOWN = 5, + BBR_PHASE_PROBE_BW_CRUISE = 6, + BBR_PHASE_PROBE_BW_REFILL = 7, }; union tcp_cc_info { --- a/misc/ss.c +++ b/misc/ss.c @@ -895,6 +895,7 @@ struct tcpstat { bool app_limited; struct dctcpstat *dctcp; struct tcp_bbr_info *bbr_info; + unsigned int bbr_info_len; }; /* SCTP assocs share the same inode number with their parent endpoint. So if we @@ -2597,6 +2598,29 @@ static void sctp_stats_print(struct sctp out(" fraginl:%d", s->sctpi_s_frag_interleave); } +static const char* bbr_phase_to_str(enum tcp_bbr_phase phase) +{ + switch (phase) { + case BBR_PHASE_STARTUP: + return "STARTUP"; + case BBR_PHASE_DRAIN: + return "DRAIN"; + case BBR_PHASE_PROBE_RTT: + return "PROBE_RTT"; + case BBR_PHASE_PROBE_BW_UP: + return "PROBE_BW_UP"; + case BBR_PHASE_PROBE_BW_DOWN: + return "PROBE_BW_DOWN"; + case BBR_PHASE_PROBE_BW_CRUISE: + return "PROBE_BW_CRUISE"; + case BBR_PHASE_PROBE_BW_REFILL: + return "PROBE_BW_REFILL"; + case BBR_PHASE_INVALID: + default: + return "INVALID"; + } +} + static void tcp_stats_print(struct tcpstat *s) { char b1[64]; @@ -2672,7 +2696,14 @@ static void tcp_stats_print(struct tcpst } if (s->bbr_info) { - __u64 bw; + /* All versions of the BBR algorithm use the INET_DIAG_BBRINFO + * enum value. Later versions of the tcp_bbr_info struct are + * backward-compatible with earlier versions, to allow older ss + * binaries to print basic information for newer versions of + * the algorithm. We use the size of the returned tcp_bbr_info + * struct to decide how much to print. + */ + __u64 bw, bw_hi, bw_lo; bw = s->bbr_info->bbr_bw_hi; bw <<= 32; @@ -2687,6 +2718,38 @@ static void tcp_stats_print(struct tcpst if (s->bbr_info->bbr_cwnd_gain) out(",cwnd_gain:%g", (double)s->bbr_info->bbr_cwnd_gain / 256.0); + + if (s->bbr_info_len >= + (offsetof(struct tcp_bbr_info, bbr_extra_acked) + + sizeof(__u32))) { + + bw_hi = s->bbr_info->bbr_bw_hi_msb; + bw_hi <<= 32; + bw_hi |= s->bbr_info->bbr_bw_hi_lsb; + + bw_lo = s->bbr_info->bbr_bw_lo_msb; + bw_lo <<= 32; + bw_lo |= s->bbr_info->bbr_bw_lo_lsb; + + out(",version:%u", s->bbr_info->bbr_version); + if (bw_hi != ~0UL) + out(",bw_hi:%sbps", sprint_bw(b1, bw_hi * 8.0)); + if (bw_lo != ~0UL) + out(",bw_lo:%sbps", sprint_bw(b1, bw_lo * 8.0)); + if (s->bbr_info->bbr_inflight_hi != ~0U) + out(",inflight_hi:%u", + s->bbr_info->bbr_inflight_hi); + if (s->bbr_info->bbr_inflight_lo != ~0U) + out(",inflight_lo:%u", + s->bbr_info->bbr_inflight_lo); + out(",extra_acked:%u", s->bbr_info->bbr_extra_acked); + out(",mode:%d", (int)s->bbr_info->bbr_mode); + out(",phase:%s", + bbr_phase_to_str( + (enum tcp_bbr_phase) + s->bbr_info->bbr_phase)); + } + out(")"); } @@ -3174,6 +3237,7 @@ static void tcp_show_info(const struct n s.bbr_info = calloc(1, sizeof(*s.bbr_info)); if (s.bbr_info && bbr_info) memcpy(s.bbr_info, bbr_info, len); + s.bbr_info_len = len; } if (rtt > 0 && info->tcpi_snd_mss && info->tcpi_snd_cwnd) {