HardenedBSD/sys/netinet/tcp_lro_hpts.c
Michael Tuexen 96ad640178 TCP LRO: add dtrace probe points
Add the IP, UDP, and TCP receive static probes to the code path,
which avoids if_input.

Reviewed by:		rrs, markj
MFC after:		1 week`
Sponsored by:		Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D43727
2024-03-08 10:21:09 +01:00

657 lines
18 KiB
C

/*-
* Copyright (c) 2016-2018 Netflix, Inc.
* Copyright (c) 2016-2021 Mellanox Technologies.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/ethernet.h>
#include <net/bpf.h>
#include <net/vnet.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <net/infiniband.h>
#include <net/if_lagg.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/ip6.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_pcb.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_lro.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_hpts.h>
#include <netinet/tcp_log_buf.h>
static void
build_ack_entry(struct tcp_ackent *ae, struct tcphdr *th, struct mbuf *m,
uint32_t *ts_ptr, uint16_t iptos)
{
/*
* Given a TCP ACK, summarize it down into the small TCP ACK
* entry.
*/
ae->timestamp = m->m_pkthdr.rcv_tstmp;
ae->flags = 0;
if (m->m_flags & M_TSTMP_LRO)
ae->flags |= TSTMP_LRO;
else if (m->m_flags & M_TSTMP)
ae->flags |= TSTMP_HDWR;
ae->seq = th->th_seq;
ae->ack = th->th_ack;
ae->flags |= tcp_get_flags(th);
if (ts_ptr != NULL) {
ae->ts_value = ntohl(ts_ptr[1]);
ae->ts_echo = ntohl(ts_ptr[2]);
ae->flags |= HAS_TSTMP;
}
ae->win = th->th_win;
ae->codepoint = iptos;
}
static inline bool
tcp_lro_ack_valid(struct mbuf *m, struct tcphdr *th, uint32_t **ppts, bool *other_opts)
{
/*
* This function returns two bits of valuable information.
* a) Is what is present capable of being ack-compressed,
* we can ack-compress if there is no options or just
* a timestamp option, and of course the th_flags must
* be correct as well.
* b) Our other options present such as SACK. This is
* used to determine if we want to wakeup or not.
*/
bool ret = true;
switch (th->th_off << 2) {
case (sizeof(*th) + TCPOLEN_TSTAMP_APPA):
*ppts = (uint32_t *)(th + 1);
/* Check if we have only one timestamp option. */
if (**ppts == TCP_LRO_TS_OPTION)
*other_opts = false;
else {
*other_opts = true;
ret = false;
}
break;
case (sizeof(*th)):
/* No options. */
*ppts = NULL;
*other_opts = false;
break;
default:
*ppts = NULL;
*other_opts = true;
ret = false;
break;
}
/* For ACKCMP we only accept ACK, PUSH, ECE and CWR. */
if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH | TH_ECE | TH_CWR)) != 0)
ret = false;
/* If it has data on it we cannot compress it */
if (m->m_pkthdr.lro_tcp_d_len)
ret = false;
/* ACK flag must be set. */
if (!(tcp_get_flags(th) & TH_ACK))
ret = false;
return (ret);
}
static bool
tcp_lro_check_wake_status(struct tcpcb *tp)
{
if (tp->t_fb->tfb_early_wake_check != NULL)
return ((tp->t_fb->tfb_early_wake_check)(tp));
return (false);
}
static void
tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
const struct lro_entry *le, const struct mbuf *m,
int frm, int32_t tcp_data_len, uint32_t th_seq,
uint32_t th_ack, uint16_t th_win)
{
if (tcp_bblogging_on(tp)) {
union tcp_log_stackspecific log;
struct timeval tv, btv;
uint32_t cts;
cts = tcp_get_usecs(&tv);
memset(&log, 0, sizeof(union tcp_log_stackspecific));
log.u_bbr.flex8 = frm;
log.u_bbr.flex1 = tcp_data_len;
if (m)
log.u_bbr.flex2 = m->m_pkthdr.len;
else
log.u_bbr.flex2 = 0;
if (le->m_head) {
log.u_bbr.flex3 = le->m_head->m_pkthdr.lro_nsegs;
log.u_bbr.flex4 = le->m_head->m_pkthdr.lro_tcp_d_len;
log.u_bbr.flex5 = le->m_head->m_pkthdr.len;
log.u_bbr.delRate = le->m_head->m_flags;
log.u_bbr.rttProp = le->m_head->m_pkthdr.rcv_tstmp;
}
log.u_bbr.inflight = th_seq;
log.u_bbr.delivered = th_ack;
log.u_bbr.timeStamp = cts;
log.u_bbr.epoch = le->next_seq;
log.u_bbr.lt_epoch = le->ack_seq;
log.u_bbr.pacing_gain = th_win;
log.u_bbr.cwnd_gain = le->window;
log.u_bbr.lost = curcpu;
log.u_bbr.cur_del_rate = (uintptr_t)m;
log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
bintime2timeval(&lc->lro_last_queue_time, &btv);
log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
log.u_bbr.flex7 = le->compressed;
log.u_bbr.pacing_gain = le->uncompressed;
if (in_epoch(net_epoch_preempt))
log.u_bbr.inhpts = 1;
else
log.u_bbr.inhpts = 0;
TCP_LOG_EVENTP(tp, NULL, &tptosocket(tp)->so_rcv,
&tptosocket(tp)->so_snd,
TCP_LOG_LRO, 0, 0, &log, false, &tv);
}
}
static struct mbuf *
tcp_lro_get_last_if_ackcmp(struct lro_ctrl *lc, struct lro_entry *le,
struct tcpcb *tp, int32_t *new_m, bool can_append_old_cmp)
{
struct mbuf *m;
/* Look at the last mbuf if any in queue */
if (can_append_old_cmp) {
m = STAILQ_LAST(&tp->t_inqueue, mbuf, m_stailqpkt);
if (m != NULL && (m->m_flags & M_ACKCMP) != 0) {
if (M_TRAILINGSPACE(m) >= sizeof(struct tcp_ackent)) {
tcp_lro_log(tp, lc, le, NULL, 23, 0, 0, 0, 0);
*new_m = 0;
counter_u64_add(tcp_extra_mbuf, 1);
return (m);
} else {
/* Mark we ran out of space */
tp->t_flags2 |= TF2_MBUF_L_ACKS;
}
}
}
/* Decide mbuf size. */
tcp_lro_log(tp, lc, le, NULL, 21, 0, 0, 0, 0);
if (tp->t_flags2 & TF2_MBUF_L_ACKS)
m = m_getcl(M_NOWAIT, MT_DATA, M_ACKCMP | M_PKTHDR);
else
m = m_gethdr(M_NOWAIT, MT_DATA);
if (__predict_false(m == NULL)) {
counter_u64_add(tcp_would_have_but, 1);
return (NULL);
}
counter_u64_add(tcp_comp_total, 1);
m->m_pkthdr.rcvif = lc->ifp;
m->m_flags |= M_ACKCMP;
*new_m = 1;
return (m);
}
/*
* Do BPF tap for either ACK_CMP packets or MBUF QUEUE type packets
* and strip all, but the IPv4/IPv6 header.
*/
static bool
do_bpf_strip_and_compress(struct tcpcb *tp, struct lro_ctrl *lc,
struct lro_entry *le, struct mbuf **pp, struct mbuf **cmp,
struct mbuf **mv_to, bool *should_wake, bool bpf_req, bool lagg_bpf_req,
struct ifnet *lagg_ifp, bool can_append_old_cmp)
{
union {
void *ptr;
struct ip *ip4;
struct ip6_hdr *ip6;
} l3;
struct mbuf *m;
struct mbuf *nm;
struct tcphdr *th;
struct tcp_ackent *ack_ent;
uint32_t *ts_ptr;
int32_t n_mbuf;
bool other_opts, can_compress;
uint8_t lro_type;
uint16_t iptos;
int tcp_hdr_offset;
int idx;
/* Get current mbuf. */
m = *pp;
/* Let the BPF see the packet */
if (__predict_false(bpf_req))
ETHER_BPF_MTAP(lc->ifp, m);
if (__predict_false(lagg_bpf_req))
ETHER_BPF_MTAP(lagg_ifp, m);
tcp_hdr_offset = m->m_pkthdr.lro_tcp_h_off;
lro_type = le->inner.data.lro_type;
switch (lro_type) {
case LRO_TYPE_NONE:
lro_type = le->outer.data.lro_type;
switch (lro_type) {
case LRO_TYPE_IPV4_TCP:
tcp_hdr_offset -= sizeof(*le->outer.ip4);
m->m_pkthdr.lro_etype = ETHERTYPE_IP;
IP_PROBE(receive, NULL, NULL, le->outer.ip4, lc->ifp,
le->outer.ip4, NULL);
break;
case LRO_TYPE_IPV6_TCP:
tcp_hdr_offset -= sizeof(*le->outer.ip6);
m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
IP_PROBE(receive, NULL, NULL, le->outer.ip6, lc->ifp,
NULL, le->outer.ip6);
break;
default:
goto compressed;
}
break;
case LRO_TYPE_IPV4_TCP:
switch (le->outer.data.lro_type) {
case LRO_TYPE_IPV4_UDP:
IP_PROBE(receive, NULL, NULL, le->outer.ip4, lc->ifp,
le->outer.ip4, NULL);
UDP_PROBE(receive, NULL, NULL, le->outer.ip4, NULL,
le->outer.udp);
break;
case LRO_TYPE_IPV6_UDP:
IP_PROBE(receive, NULL, NULL, le->outer.ip6, lc->ifp,
NULL, le->outer.ip6);
UDP_PROBE(receive, NULL, NULL, le->outer.ip6, NULL,
le->outer.udp);
break;
default:
__assert_unreachable();
break;
}
tcp_hdr_offset -= sizeof(*le->outer.ip4);
m->m_pkthdr.lro_etype = ETHERTYPE_IP;
IP_PROBE(receive, NULL, NULL, le->inner.ip4, NULL,
le->inner.ip4, NULL);
break;
case LRO_TYPE_IPV6_TCP:
switch (le->outer.data.lro_type) {
case LRO_TYPE_IPV4_UDP:
IP_PROBE(receive, NULL, NULL, le->outer.ip4, lc->ifp,
le->outer.ip4, NULL);
UDP_PROBE(receive, NULL, NULL, le->outer.ip4, NULL,
le->outer.udp);
break;
case LRO_TYPE_IPV6_UDP:
IP_PROBE(receive, NULL, NULL, le->outer.ip6, lc->ifp,
NULL, le->outer.ip6);
UDP_PROBE(receive, NULL, NULL, le->outer.ip6, NULL,
le->outer.udp);
break;
default:
__assert_unreachable();
break;
}
tcp_hdr_offset -= sizeof(*le->outer.ip6);
m->m_pkthdr.lro_etype = ETHERTYPE_IPV6;
IP_PROBE(receive, NULL, NULL, le->inner.ip6, NULL, NULL,
le->inner.ip6);
break;
default:
goto compressed;
}
MPASS(tcp_hdr_offset >= 0);
m_adj(m, tcp_hdr_offset);
m->m_flags |= M_LRO_EHDRSTRP;
m->m_flags &= ~M_ACKCMP;
m->m_pkthdr.lro_tcp_h_off -= tcp_hdr_offset;
th = tcp_lro_get_th(m);
th->th_sum = 0; /* TCP checksum is valid. */
tcp_fields_to_host(th);
TCP_PROBE5(receive, NULL, tp, m, tp, th);
/* Check if ACK can be compressed */
can_compress = tcp_lro_ack_valid(m, th, &ts_ptr, &other_opts);
/* Now lets look at the should wake states */
if ((other_opts == true) &&
((tp->t_flags2 & TF2_DONT_SACK_QUEUE) == 0)) {
/*
* If there are other options (SACK?) and the
* tcp endpoint has not expressly told us it does
* not care about SACKS, then we should wake up.
*/
*should_wake = true;
} else if (*should_wake == false) {
/* Wakeup override check if we are false here */
*should_wake = tcp_lro_check_wake_status(tp);
}
/* Is the ack compressable? */
if (can_compress == false)
goto done;
/* Does the TCP endpoint support ACK compression? */
if ((tp->t_flags2 & TF2_MBUF_ACKCMP) == 0)
goto done;
/* Lets get the TOS/traffic class field */
l3.ptr = mtod(m, void *);
switch (lro_type) {
case LRO_TYPE_IPV4_TCP:
iptos = l3.ip4->ip_tos;
break;
case LRO_TYPE_IPV6_TCP:
iptos = IPV6_TRAFFIC_CLASS(l3.ip6);
break;
default:
iptos = 0; /* Keep compiler happy. */
break;
}
/* Now lets get space if we don't have some already */
if (*cmp == NULL) {
new_one:
nm = tcp_lro_get_last_if_ackcmp(lc, le, tp, &n_mbuf,
can_append_old_cmp);
if (__predict_false(nm == NULL))
goto done;
*cmp = nm;
if (n_mbuf) {
/*
* Link in the new cmp ack to our in-order place,
* first set our cmp ack's next to where we are.
*/
nm->m_nextpkt = m;
(*pp) = nm;
/*
* Set it up so mv_to is advanced to our
* compressed ack. This way the caller can
* advance pp to the right place.
*/
*mv_to = nm;
/*
* Advance it here locally as well.
*/
pp = &nm->m_nextpkt;
}
} else {
/* We have one already we are working on */
nm = *cmp;
if (M_TRAILINGSPACE(nm) < sizeof(struct tcp_ackent)) {
/* We ran out of space */
tp->t_flags2 |= TF2_MBUF_L_ACKS;
goto new_one;
}
}
MPASS(M_TRAILINGSPACE(nm) >= sizeof(struct tcp_ackent));
counter_u64_add(tcp_inp_lro_compressed, 1);
le->compressed++;
/* We can add in to the one on the tail */
ack_ent = mtod(nm, struct tcp_ackent *);
idx = (nm->m_len / sizeof(struct tcp_ackent));
build_ack_entry(&ack_ent[idx], th, m, ts_ptr, iptos);
/* Bump the size of both pkt-hdr and len */
nm->m_len += sizeof(struct tcp_ackent);
nm->m_pkthdr.len += sizeof(struct tcp_ackent);
compressed:
/* Advance to next mbuf before freeing. */
*pp = m->m_nextpkt;
m->m_nextpkt = NULL;
m_freem(m);
return (true);
done:
counter_u64_add(tcp_uncomp_total, 1);
le->uncompressed++;
return (false);
}
static void
tcp_queue_pkts(struct tcpcb *tp, struct lro_entry *le)
{
INP_WLOCK_ASSERT(tptoinpcb(tp));
STAILQ_HEAD(, mbuf) q = { le->m_head,
&STAILQ_NEXT(le->m_last_mbuf, m_stailqpkt) };
STAILQ_CONCAT(&tp->t_inqueue, &q);
le->m_head = NULL;
le->m_last_mbuf = NULL;
}
static struct tcpcb *
tcp_lro_lookup(struct ifnet *ifp, struct lro_parser *pa)
{
struct inpcb *inp;
CURVNET_ASSERT_SET();
switch (pa->data.lro_type) {
#ifdef INET6
case LRO_TYPE_IPV6_TCP:
inp = in6_pcblookup(&V_tcbinfo,
&pa->data.s_addr.v6,
pa->data.s_port,
&pa->data.d_addr.v6,
pa->data.d_port,
INPLOOKUP_WLOCKPCB,
ifp);
break;
#endif
#ifdef INET
case LRO_TYPE_IPV4_TCP:
inp = in_pcblookup(&V_tcbinfo,
pa->data.s_addr.v4,
pa->data.s_port,
pa->data.d_addr.v4,
pa->data.d_port,
INPLOOKUP_WLOCKPCB,
ifp);
break;
#endif
default:
return (NULL);
}
return (intotcpcb(inp));
}
static int
_tcp_lro_flush_tcphpts(struct lro_ctrl *lc, struct lro_entry *le)
{
struct tcpcb *tp;
struct mbuf **pp, *cmp, *mv_to;
struct ifnet *lagg_ifp;
bool bpf_req, lagg_bpf_req, should_wake, can_append_old_cmp;
/* Check if packet doesn't belongs to our network interface. */
if ((tcplro_stacks_wanting_mbufq == 0) ||
(le->outer.data.vlan_id != 0) ||
(le->inner.data.lro_type != LRO_TYPE_NONE))
return (TCP_LRO_CANNOT);
#ifdef INET6
/*
* Be proactive about unspecified IPv6 address in source. As
* we use all-zero to indicate unbounded/unconnected pcb,
* unspecified IPv6 address can be used to confuse us.
*
* Note that packets with unspecified IPv6 destination is
* already dropped in ip6_input.
*/
if (__predict_false(le->outer.data.lro_type == LRO_TYPE_IPV6_TCP &&
IN6_IS_ADDR_UNSPECIFIED(&le->outer.data.s_addr.v6)))
return (TCP_LRO_CANNOT);
if (__predict_false(le->inner.data.lro_type == LRO_TYPE_IPV6_TCP &&
IN6_IS_ADDR_UNSPECIFIED(&le->inner.data.s_addr.v6)))
return (TCP_LRO_CANNOT);
#endif
CURVNET_SET(lc->ifp->if_vnet);
/*
* Ensure that there are no packet filter hooks which would normally
* being triggered in ether_demux(), ip_input(), or ip6_input().
*/
if (
#ifdef INET
PFIL_HOOKED_IN(V_inet_pfil_head) ||
#endif
#ifdef INET6
PFIL_HOOKED_IN(V_inet6_pfil_head) ||
#endif
PFIL_HOOKED_IN(V_link_pfil_head)) {
CURVNET_RESTORE();
return (TCP_LRO_CANNOT);
}
/* Lookup inp, if any. Returns locked TCP inpcb. */
tp = tcp_lro_lookup(lc->ifp,
(le->inner.data.lro_type == LRO_TYPE_NONE) ? &le->outer : &le->inner);
CURVNET_RESTORE();
if (tp == NULL)
return (TCP_LRO_CANNOT);
counter_u64_add(tcp_inp_lro_locks_taken, 1);
/* Check if the inp is dead, Jim. */
if (tp->t_state == TCPS_TIME_WAIT) {
INP_WUNLOCK(tptoinpcb(tp));
return (TCP_LRO_CANNOT);
}
if (tp->t_lro_cpu == HPTS_CPU_NONE && lc->lro_cpu_is_set == 1)
tp->t_lro_cpu = lc->lro_last_cpu;
/* Check if the transport doesn't support the needed optimizations. */
if ((tp->t_flags2 & (TF2_SUPPORTS_MBUFQ | TF2_MBUF_ACKCMP)) == 0) {
INP_WUNLOCK(tptoinpcb(tp));
return (TCP_LRO_CANNOT);
}
if (tp->t_flags2 & TF2_MBUF_QUEUE_READY)
should_wake = false;
else
should_wake = true;
/* Check if packets should be tapped to BPF. */
bpf_req = bpf_peers_present(lc->ifp->if_bpf);
lagg_bpf_req = false;
lagg_ifp = NULL;
if (lc->ifp->if_type == IFT_IEEE8023ADLAG ||
lc->ifp->if_type == IFT_INFINIBANDLAG) {
struct lagg_port *lp = lc->ifp->if_lagg;
struct lagg_softc *sc = lp->lp_softc;
lagg_ifp = sc->sc_ifp;
if (lagg_ifp != NULL)
lagg_bpf_req = bpf_peers_present(lagg_ifp->if_bpf);
}
/* Strip and compress all the incoming packets. */
can_append_old_cmp = true;
cmp = NULL;
for (pp = &le->m_head; *pp != NULL; ) {
mv_to = NULL;
if (do_bpf_strip_and_compress(tp, lc, le, pp, &cmp, &mv_to,
&should_wake, bpf_req, lagg_bpf_req, lagg_ifp,
can_append_old_cmp) == false) {
/* Advance to next mbuf. */
pp = &(*pp)->m_nextpkt;
/*
* Once we have appended we can't look in the pending
* inbound packets for a compressed ack to append to.
*/
can_append_old_cmp = false;
/*
* Once we append we also need to stop adding to any
* compressed ack we were remembering. A new cmp
* ack will be required.
*/
cmp = NULL;
tcp_lro_log(tp, lc, le, NULL, 25, 0, 0, 0, 0);
} else if (mv_to != NULL) {
/* We are asked to move pp up */
pp = &mv_to->m_nextpkt;
tcp_lro_log(tp, lc, le, NULL, 24, 0, 0, 0, 0);
} else
tcp_lro_log(tp, lc, le, NULL, 26, 0, 0, 0, 0);
}
/* Update "m_last_mbuf", if any. */
if (pp == &le->m_head)
le->m_last_mbuf = *pp;
else
le->m_last_mbuf = __containerof(pp, struct mbuf, m_nextpkt);
/* Check if any data mbufs left. */
if (le->m_head != NULL) {
counter_u64_add(tcp_inp_lro_direct_queue, 1);
tcp_lro_log(tp, lc, le, NULL, 22, 1, tp->t_flags2, 0, 1);
tcp_queue_pkts(tp, le);
}
if (should_wake) {
/* Wakeup */
counter_u64_add(tcp_inp_lro_wokeup_queue, 1);
if ((*tp->t_fb->tfb_do_queued_segments)(tp, 0))
/* TCP cb gone and unlocked. */
return (0);
}
INP_WUNLOCK(tptoinpcb(tp));
return (0); /* Success. */
}
void
tcp_lro_hpts_init(void)
{
tcp_lro_flush_tcphpts = _tcp_lro_flush_tcphpts;
}
void
tcp_lro_hpts_uninit(void)
{
atomic_store_ptr(&tcp_lro_flush_tcphpts, NULL);
}