grpc/src/core/lib/iomgr/internal_errqueue.h

/*
 *
 * Copyright 2018 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

/* This file contains constants defined in <linux/errqueue.h> and
 * <linux/net_tstamp.h> so as to allow collecting network timestamps in the
 * kernel. This file allows tcp_posix.cc to compile on platforms that do not
 * have <linux/errqueue.h> and <linux/net_tstamp.h>.
 */

#ifndef GRPC_CORE_LIB_IOMGR_INTERNAL_ERRQUEUE_H
#define GRPC_CORE_LIB_IOMGR_INTERNAL_ERRQUEUE_H

#include <grpc/support/port_platform.h>

#include "src/core/lib/iomgr/port.h"

#ifdef GRPC_POSIX_SOCKET_TCP

#include <sys/types.h>
#include <time.h>

#ifdef GRPC_LINUX_ERRQUEUE
#include <linux/errqueue.h>
#include <linux/net_tstamp.h>
#include <linux/netlink.h>
#include <sys/socket.h>
#endif /* GRPC_LINUX_ERRQUEUE */

namespace grpc_core {

#ifdef GRPC_LINUX_ERRQUEUE

/* Redefining scm_timestamping in the same way that <linux/errqueue.h> defines
 * it, so that code compiles on systems that don't have it. */
struct scm_timestamping {
  struct timespec ts[3];
};
/* Also redefine timestamp types */
/* The timestamp type for when the driver passed skb to NIC, or HW. */
constexpr int SCM_TSTAMP_SND = 0;
/* The timestamp type for when data entered the packet scheduler. */
constexpr int SCM_TSTAMP_SCHED = 1;
/* The timestamp type for when data acknowledged by peer. */
constexpr int SCM_TSTAMP_ACK = 2;

/* Control message type containing OPT_STATS */
#ifndef SCM_TIMESTAMPING_OPT_STATS
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif

/* Redefine required constants from <linux/net_tstamp.h> */
constexpr uint32_t SOF_TIMESTAMPING_TX_SOFTWARE = 1u << 1;
constexpr uint32_t SOF_TIMESTAMPING_SOFTWARE = 1u << 4;
constexpr uint32_t SOF_TIMESTAMPING_OPT_ID = 1u << 7;
constexpr uint32_t SOF_TIMESTAMPING_TX_SCHED = 1u << 8;
constexpr uint32_t SOF_TIMESTAMPING_TX_ACK = 1u << 9;
constexpr uint32_t SOF_TIMESTAMPING_OPT_TSONLY = 1u << 11;
constexpr uint32_t SOF_TIMESTAMPING_OPT_STATS = 1u << 12;

constexpr uint32_t kTimestampingSocketOptions =
    SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_OPT_ID |
    SOF_TIMESTAMPING_OPT_TSONLY | SOF_TIMESTAMPING_OPT_STATS;
constexpr uint32_t kTimestampingRecordingOptions =
    SOF_TIMESTAMPING_TX_SCHED | SOF_TIMESTAMPING_TX_SOFTWARE |
    SOF_TIMESTAMPING_TX_ACK;

/* Netlink attribute types used for TCP opt stats. */
enum TCPOptStats {
  TCP_NLA_PAD,
  TCP_NLA_BUSY,           /* Time (usec) busy sending data. */
  TCP_NLA_RWND_LIMITED,   /* Time (usec) limited by receive window. */
  TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer. */
  TCP_NLA_DATA_SEGS_OUT,  /* Data pkts sent including retransmission. */
  TCP_NLA_TOTAL_RETRANS,  /* Data pkts retransmitted. */
  TCP_NLA_PACING_RATE,    /* Pacing rate in Bps. */
  TCP_NLA_DELIVERY_RATE,  /* Delivery rate in Bps. */
  TCP_NLA_SND_CWND,       /* Sending congestion window. */
  TCP_NLA_REORDERING,     /* Reordering metric. */
  TCP_NLA_MIN_RTT,        /* minimum RTT. */
  TCP_NLA_RECUR_RETRANS,  /* Recurring retransmits for the current pkt. */
  TCP_NLA_DELIVERY_RATE_APP_LMT, /* Delivery rate application limited? */
  TCP_NLA_SNDQ_SIZE,             /* Data (bytes) pending in send queue */
  TCP_NLA_CA_STATE,              /* ca_state of socket */
  TCP_NLA_SND_SSTHRESH,          /* Slow start size threshold */
  TCP_NLA_DELIVERED,             /* Data pkts delivered incl. out-of-order */
  TCP_NLA_DELIVERED_CE,          /* Like above but only ones w/ CE marks */
  TCP_NLA_BYTES_SENT,            /* Data bytes sent including retransmission */
  TCP_NLA_BYTES_RETRANS,         /* Data bytes retransmitted */
  TCP_NLA_DSACK_DUPS,            /* DSACK blocks received */
  TCP_NLA_REORD_SEEN,            /* reordering events seen */
  TCP_NLA_SRTT,                  /* smoothed RTT in usecs */
};

/* tcp_info from from linux/tcp.h */
struct tcp_info {
  uint8_t tcpi_state;
  uint8_t tcpi_ca_state;
  uint8_t tcpi_retransmits;
  uint8_t tcpi_probes;
  uint8_t tcpi_backoff;
  uint8_t tcpi_options;
  uint8_t tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
  uint8_t tcpi_delivery_rate_app_limited : 1;
  uint32_t tcpi_rto;
  uint32_t tcpi_ato;
  uint32_t tcpi_snd_mss;
  uint32_t tcpi_rcv_mss;
  uint32_t tcpi_unacked;
  uint32_t tcpi_sacked;
  uint32_t tcpi_lost;
  uint32_t tcpi_retrans;
  uint32_t tcpi_fackets;
  /* Times. */
  uint32_t tcpi_last_data_sent;
  uint32_t tcpi_last_ack_sent; /* Not remembered, sorry. */
  uint32_t tcpi_last_data_recv;
  uint32_t tcpi_last_ack_recv;
  /* Metrics. */
  uint32_t tcpi_pmtu;
  uint32_t tcpi_rcv_ssthresh;
  uint32_t tcpi_rtt;
  uint32_t tcpi_rttvar;
  uint32_t tcpi_snd_ssthresh;
  uint32_t tcpi_snd_cwnd;
  uint32_t tcpi_advmss;
  uint32_t tcpi_reordering;
  uint32_t tcpi_rcv_rtt;
  uint32_t tcpi_rcv_space;
  uint32_t tcpi_total_retrans;
  uint64_t tcpi_pacing_rate;
  uint64_t tcpi_max_pacing_rate;
  uint64_t tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
  uint64_t tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */

  uint32_t tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
  uint32_t tcpi_segs_in;  /* RFC4898 tcpEStatsPerfSegsIn */
  uint32_t tcpi_notsent_bytes;
  uint32_t tcpi_min_rtt;

  uint32_t tcpi_data_segs_in;  /* RFC4898 tcpEStatsDataSegsIn */
  uint32_t tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */

  uint64_t tcpi_delivery_rate;
  uint64_t tcpi_busy_time;      /* Time (usec) busy sending data */
  uint64_t tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
  uint64_t tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */

  uint32_t tcpi_delivered;
  uint32_t tcpi_delivered_ce;
  uint64_t tcpi_bytes_sent;    /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
  uint64_t tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
  uint32_t tcpi_dsack_dups;    /* RFC4898 tcpEStatsStackDSACKDups */
  uint32_t tcpi_reord_seen;    /* reordering events seen */
  socklen_t length;            /* Length of struct returned by kernel */
};

#ifndef TCP_INFO
#define TCP_INFO 11
#endif
#endif /* GRPC_LINUX_ERRQUEUE */

/* Returns true if kernel is capable of supporting errqueue and timestamping.
 * Currently allowing only linux kernels above 4.0.0
 */
bool kernel_supports_errqueue();

} /* namespace grpc_core */

#endif /* GRPC_POSIX_SOCKET_TCP */

namespace grpc_core {
/* Initializes errqueue support */
void grpc_errqueue_init();
} /* namespace grpc_core */

#endif /* GRPC_CORE_LIB_IOMGR_INTERNAL_ERRQUEUE_H */