cregit-Linux how code gets into the kernel

Release 4.11 net/ipv4/inet_connection_sock.c

Directory: net/ipv4
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              Support for INET connection oriented protocols.
 *
 * Authors:     See the TCP sources
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or(at your option) any later version.
 */

#include <linux/module.h>
#include <linux/jhash.h>

#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp_states.h>
#include <net/xfrm.h>
#include <net/tcp.h>
#include <net/sock_reuseport.h>

#ifdef INET_CSK_DEBUG

const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";

EXPORT_SYMBOL(inet_csk_timer_bug_msg);
#endif

#if IS_ENABLED(CONFIG_IPV6)
/* match_wildcard == true:  IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
 *                          only, and any IPv4 addresses if not IPv6 only
 * match_wildcard == false: addresses must be exactly the same, i.e.
 *                          IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
 *                          and 0.0.0.0 equals to 0.0.0.0 only
 */

static int ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6, const struct in6_addr *sk2_rcv_saddr6, __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, bool sk1_ipv6only, bool sk2_ipv6only, bool match_wildcard) { int addr_type = ipv6_addr_type(sk1_rcv_saddr6); int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED; /* if both are mapped, treat as IPv4 */ if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) { if (!sk2_ipv6only) { if (sk1_rcv_saddr == sk2_rcv_saddr) return 1; if (!sk1_rcv_saddr || !sk2_rcv_saddr) return match_wildcard; } return 0; } if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY) return 1; if (addr_type2 == IPV6_ADDR_ANY && match_wildcard && !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED)) return 1; if (addr_type == IPV6_ADDR_ANY && match_wildcard && !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED)) return 1; if (sk2_rcv_saddr6 && ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6)) return 1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Josef Bacik166100.00%2100.00%
Total166100.00%2100.00%

#endif /* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses * match_wildcard == false: addresses must be exactly the same, i.e. * 0.0.0.0 only equals to 0.0.0.0 */
static int ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, bool sk2_ipv6only, bool match_wildcard) { if (!sk2_ipv6only) { if (sk1_rcv_saddr == sk2_rcv_saddr) return 1; if (!sk1_rcv_saddr || !sk2_rcv_saddr) return match_wildcard; } return 0; }

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Josef Bacik48100.00%2100.00%
Total48100.00%2100.00%


int inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2, bool match_wildcard) { #if IS_ENABLED(CONFIG_IPV6) if (sk->sk_family == AF_INET6) return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr, inet6_rcv_saddr(sk2), sk->sk_rcv_saddr, sk2->sk_rcv_saddr, ipv6_only_sock(sk), ipv6_only_sock(sk2), match_wildcard); #endif return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr, ipv6_only_sock(sk2), match_wildcard); }

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Josef Bacik89100.00%3100.00%
Total89100.00%3100.00%

EXPORT_SYMBOL(inet_rcv_saddr_equal);
void inet_get_local_port_range(struct net *net, int *low, int *high) { unsigned int seq; do { seq = read_seqbegin(&net->ipv4.ip_local_ports.lock); *low = net->ipv4.ip_local_ports.range[0]; *high = net->ipv4.ip_local_ports.range[1]; } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq)); }

Contributors

PersonTokensPropCommitsCommitProp
Stephen Hemminger5059.52%120.00%
Eric W. Biedermann2125.00%120.00%
Eric Dumazet910.71%240.00%
Américo Wang44.76%120.00%
Total84100.00%5100.00%

EXPORT_SYMBOL(inet_get_local_port_range);
static int inet_csk_bind_conflict(const struct sock *sk, const struct inet_bind_bucket *tb, bool relax, bool reuseport_ok) { struct sock *sk2; bool reuse = sk->sk_reuse; bool reuseport = !!sk->sk_reuseport && reuseport_ok; kuid_t uid = sock_i_uid((struct sock *)sk); /* * Unlike other sk lookup places we do not check * for sk_net here, since _all_ the socks listed * in tb->owners list belong to the same net - the * one this bucket belongs to. */ sk_for_each_bound(sk2, &tb->owners) { if (sk != sk2 && (!sk->sk_bound_dev_if || !sk2->sk_bound_dev_if || sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { if ((!reuse || !sk2->sk_reuse || sk2->sk_state == TCP_LISTEN) && (!reuseport || !sk2->sk_reuseport || rcu_access_pointer(sk->sk_reuseport_cb) || (sk2->sk_state != TCP_TIME_WAIT && !uid_eq(uid, sock_i_uid(sk2))))) { if (inet_rcv_saddr_equal(sk, sk2, true)) break; } if (!relax && reuse && sk2->sk_reuse && sk2->sk_state != TCP_LISTEN) { if (inet_rcv_saddr_equal(sk, sk2, true)) break; } } } return sk2 != NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo8843.78%216.67%
Tom Herbert5929.35%216.67%
Alexandru Copot2713.43%18.33%
Josef Bacik136.47%18.33%
Craig Gallek73.48%18.33%
Eric Dumazet31.49%216.67%
David S. Miller21.00%18.33%
Pavel Emelyanov10.50%18.33%
Sasha Levin10.50%18.33%
Total201100.00%12100.00%

/* * Find an open port number for the socket. Returns with the * inet_bind_hashbucket lock held. */
static struct inet_bind_hashbucket * inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret) { struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; int port = 0; struct inet_bind_hashbucket *head; struct net *net = sock_net(sk); int i, low, high, attempt_half; struct inet_bind_bucket *tb; u32 remaining, offset; attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; other_half_scan: inet_get_local_port_range(net, &low, &high); high++; /* [32768, 60999] -> [32768, 61000[ */ if (high - low < 4) attempt_half = 0; if (attempt_half) { int half = low + (((high - low) >> 2) << 1); if (attempt_half == 1) high = half; else low = half; } remaining = high - low; if (likely(remaining > 1)) remaining &= ~1U; offset = prandom_u32() % remaining; /* __inet_hash_connect() favors ports having @low parity * We do the opposite to not pollute connect() users. */ offset |= 1U; other_parity_scan: port = low + offset; for (i = 0; i < remaining; i += 2, port += 2) { if (unlikely(port >= high)) port -= remaining; if (inet_is_local_reserved_port(net, port)) continue; head = &hinfo->bhash[inet_bhashfn(net, port, hinfo->bhash_size)]; spin_lock_bh(&head->lock); inet_bind_bucket_for_each(tb, &head->chain) if (net_eq(ib_net(tb), net) && tb->port == port) { if (!inet_csk_bind_conflict(sk, tb, false, false)) goto success; goto next_port; } tb = NULL; goto success; next_port: spin_unlock_bh(&head->lock); cond_resched(); } offset--; if (!(offset & 1)) goto other_parity_scan; if (attempt_half == 1) { /* OK we now try the upper half of the range */ attempt_half = 2; goto other_half_scan; } return NULL; success: *port_ret = port; *tb_ret = tb; return head; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet20052.22%312.00%
Arnaldo Carvalho de Melo7018.28%312.00%
Josef Bacik4110.70%312.00%
Stephen Hemminger164.18%28.00%
Pavel Emelyanov164.18%312.00%
Flavio Leitner92.35%14.00%
Evgeniy Polyakov92.35%14.00%
Américo Wang82.09%28.00%
Octavian Purdila41.04%14.00%
Hideaki Yoshifuji / 吉藤英明30.78%14.00%
Alexandru Copot20.52%14.00%
Eric W. Biedermann20.52%14.00%
Aruna-Hewapathirane10.26%14.00%
Tom Herbert10.26%14.00%
Anton Arapov10.26%14.00%
Total383100.00%25100.00%


static inline int sk_reuseport_match(struct inet_bind_bucket *tb, struct sock *sk) { kuid_t uid = sock_i_uid(sk); if (tb->fastreuseport <= 0) return 0; if (!sk->sk_reuseport) return 0; if (rcu_access_pointer(sk->sk_reuseport_cb)) return 0; if (!uid_eq(tb->fastuid, uid)) return 0; /* We only need to check the rcv_saddr if this tb was once marked * without fastreuseport and then was reset, as we can only know that * the fast_*rcv_saddr doesn't have any conflicts with the socks on the * owners list. */ if (tb->fastreuseport == FASTREUSEPORT_ANY) return 1; #if IS_ENABLED(CONFIG_IPV6) if (tb->fast_sk_family == AF_INET6) return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr, &sk->sk_v6_rcv_saddr, tb->fast_rcv_saddr, sk->sk_rcv_saddr, tb->fast_ipv6_only, ipv6_only_sock(sk), true); #endif return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr, ipv6_only_sock(sk), true); }

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Josef Bacik153100.00%1100.00%
Total153100.00%1100.00%

/* Obtain a reference to a local port for the given sock, * if snum is zero it means select any available local port. * We try to allocate an odd port (and leave even ports for connect()) */
int inet_csk_get_port(struct sock *sk, unsigned short snum) { bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; int ret = 1, port = snum; struct inet_bind_hashbucket *head; struct net *net = sock_net(sk); struct inet_bind_bucket *tb = NULL; kuid_t uid = sock_i_uid(sk); if (!port) { head = inet_csk_find_open_port(sk, &tb, &port); if (!head) return ret; if (!tb) goto tb_not_found; goto success; } head = &hinfo->bhash[inet_bhashfn(net, port, hinfo->bhash_size)]; spin_lock_bh(&head->lock); inet_bind_bucket_for_each(tb, &head->chain) if (net_eq(ib_net(tb), net) && tb->port == port) goto tb_found; tb_not_found: tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net, head, port); if (!tb) goto fail_unlock; tb_found: if (!hlist_empty(&tb->owners)) { if (sk->sk_reuse == SK_FORCE_REUSE) goto success; if ((tb->fastreuse > 0 && reuse) || sk_reuseport_match(tb, sk)) goto success; if (inet_csk_bind_conflict(sk, tb, true, true)) goto fail_unlock; } success: if (!hlist_empty(&tb->owners)) { tb->fastreuse = reuse; if (sk->sk_reuseport) { tb->fastreuseport = FASTREUSEPORT_ANY; tb->fastuid = uid; tb->fast_rcv_saddr = sk->sk_rcv_saddr; tb->fast_ipv6_only = ipv6_only_sock(sk); #if IS_ENABLED(CONFIG_IPV6) tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; #endif } else { tb->fastreuseport = 0; } } else { if (!reuse) tb->fastreuse = 0; if (sk->sk_reuseport) { /* We didn't match or we don't have fastreuseport set on * the tb, but we have sk_reuseport set on this socket * and we know that there are no bind conflicts with * this socket in this tb, so reset our tb's reuseport * settings so that any subsequent sockets that match * our current socket will be put on the fast path. * * If we reset we need to set FASTREUSEPORT_STRICT so we * do extra checking for all subsequent sk_reuseport * socks. */ if (!sk_reuseport_match(tb, sk)) { tb->fastreuseport = FASTREUSEPORT_STRICT; tb->fastuid = uid; tb->fast_rcv_saddr = sk->sk_rcv_saddr; tb->fast_ipv6_only = ipv6_only_sock(sk); #if IS_ENABLED(CONFIG_IPV6) tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; #endif } } else { tb->fastreuseport = 0; } } if (!inet_csk(sk)->icsk_bind_hash) inet_bind_hash(sk, tb, port); WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); ret = 0; fail_unlock: spin_unlock_bh(&head->lock); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Josef Bacik29661.54%426.67%
Arnaldo Carvalho de Melo10722.25%16.67%
Tom Herbert285.82%213.33%
Eric Dumazet275.61%16.67%
Pavel Emelyanov132.70%320.00%
Evgeniy Polyakov51.04%16.67%
Ilpo Järvinen20.42%16.67%
Alexandru Copot20.42%16.67%
Craig Gallek10.21%16.67%
Total481100.00%15100.00%

EXPORT_SYMBOL_GPL(inet_csk_get_port); /* * Wait for an incoming connection, avoid race conditions. This must be called * with the socket locked. */
static int inet_csk_wait_for_connect(struct sock *sk, long timeo) { struct inet_connection_sock *icsk = inet_csk(sk); DEFINE_WAIT(wait); int err; /* * True wake-one mechanism for incoming connections: only * one process gets woken up, not the 'whole herd'. * Since we do not 'race & poll' for established sockets * anymore, the common case will execute the loop only once. * * Subtle issue: "add_wait_queue_exclusive()" will be added * after any current non-exclusive waiters, and we know that * it will always _stay_ after any new non-exclusive waiters * because all non-exclusive waiters are added at the * beginning of the wait-queue. As such, it's ok to "drop" * our exclusiveness temporarily when we get woken up without * having to remove and re-insert us on the wait queue. */ for (;;) { prepare_to_wait_exclusive(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); release_sock(sk); if (reqsk_queue_empty(&icsk->icsk_accept_queue)) timeo = schedule_timeout(timeo); sched_annotate_sleep(); lock_sock(sk); err = 0; if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) break; err = -EINVAL; if (sk->sk_state != TCP_LISTEN) break; err = sock_intr_errno(timeo); if (signal_pending(current)) break; err = -EAGAIN; if (!timeo) break; } finish_wait(sk_sleep(sk), &wait); return err; }

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Arnaldo Carvalho de Melo14494.12%133.33%
Eric Dumazet95.88%266.67%
Total153100.00%3100.00%

/* * This will accept the next outstanding connection. */
struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) { struct inet_connection_sock *icsk = inet_csk(sk); struct request_sock_queue *queue = &icsk->icsk_accept_queue; struct request_sock *req; struct sock *newsk; int error; lock_sock(sk); /* We need to make sure that this socket is listening, * and that it has something pending. */ error = -EINVAL; if (sk->sk_state != TCP_LISTEN) goto out_err; /* Find already established connection */ if (reqsk_queue_empty(queue)) { long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); /* If this is a non blocking socket don't sleep */ error = -EAGAIN; if (!timeo) goto out_err; error = inet_csk_wait_for_connect(sk, timeo); if (error) goto out_err; } req = reqsk_queue_remove(queue, sk); newsk = req->sk; if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { spin_lock_bh(&queue->fastopenq.lock); if (tcp_rsk(req)->tfo_listener) { /* We are still waiting for the final ACK from 3WHS * so can't free req now. Instead, we set req->sk to * NULL to signify that the child socket is taken * so reqsk_fastopen_remove() will free the req * when 3WHS finishes (or is aborted). */ req->sk = NULL; req = NULL; } spin_unlock_bh(&queue->fastopenq.lock); } out: release_sock(sk); if (req) reqsk_put(req); return newsk; out_err: newsk = NULL; req = NULL; *err = error; goto out; }

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PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo14359.58%111.11%
Jerry Chu7631.67%111.11%
Eric Dumazet187.50%666.67%
David Howells31.25%111.11%
Total240100.00%9100.00%

EXPORT_SYMBOL(inet_csk_accept); /* * Using different timers for retransmit, delayed acks and probes * We may wish use just one timer maintaining a list of expire jiffies * to optimize. */
void inet_csk_init_xmit_timers(struct sock *sk, void (*retransmit_handler)(unsigned long), void (*delack_handler)(unsigned long), void (*keepalive_handler)(unsigned long)) { struct inet_connection_sock *icsk = inet_csk(sk); setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler, (unsigned long)sk); setup_timer(&icsk->icsk_delack_timer, delack_handler, (unsigned long)sk); setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk); icsk->icsk_pending = icsk->icsk_ack.pending = 0; }

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PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo8880.00%150.00%
Pavel Emelyanov2220.00%150.00%
Total110100.00%2100.00%

EXPORT_SYMBOL(inet_csk_init_xmit_timers);
void inet_csk_clear_xmit_timers(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0; sk_stop_timer(sk, &icsk->icsk_retransmit_timer); sk_stop_timer(sk, &icsk->icsk_delack_timer); sk_stop_timer(sk, &sk->sk_timer); }

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PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo68100.00%1100.00%
Total68100.00%1100.00%

EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
void inet_csk_delete_keepalive_timer(struct sock *sk) { sk_stop_timer(sk, &sk->sk_timer); }

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Arnaldo Carvalho de Melo20100.00%1100.00%
Total20100.00%1100.00%

EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) { sk_reset_timer(sk, &sk->sk_timer, jiffies + len); }

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Arnaldo Carvalho de Melo28100.00%1100.00%
Total28100.00%1100.00%

EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4, const struct request_sock *req) { const struct inet_request_sock *ireq = inet_rsk(req); struct net *net = read_pnet(&ireq->ireq_net); struct ip_options_rcu *opt = ireq->opt; struct rtable *rt; flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, sk->sk_protocol, inet_sk_flowi_flags(sk), (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, ireq->ir_loc_addr, ireq->ir_rmt_port, htons(ireq->ir_num), sk->sk_uid); security_req_classify_flow(req, flowi4_to_flowi(fl4)); rt = ip_route_output_flow(net, fl4, sk); if (IS_ERR(rt)) goto no_route; if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) goto route_err; return &rt->dst; route_err: ip_rt_put(rt); no_route: __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo8340.89%14.76%
David S. Miller4723.15%419.05%
Eric Dumazet3818.72%628.57%
Ilpo Järvinen167.88%14.76%
Venkat Yekkirala62.96%29.52%
Lorenzo Colitti62.96%29.52%
Pavel Emelyanov41.97%29.52%
Atis Elsts10.49%14.76%
Denis V. Lunev10.49%14.76%
Julian Anastasov10.49%14.76%
Total203100.00%21100.00%

EXPORT_SYMBOL_GPL(inet_csk_route_req);
struct dst_entry *inet_csk_route_child_sock(const struct sock *sk, struct sock *newsk, const struct request_sock *req) { const struct inet_request_sock *ireq = inet_rsk(req); struct net *net = read_pnet(&ireq->ireq_net); struct inet_sock *newinet = inet_sk(newsk); struct ip_options_rcu *opt; struct flowi4 *fl4; struct rtable *rt; fl4 = &newinet->cork.fl.u.ip4; rcu_read_lock(); opt = rcu_dereference(newinet->inet_opt); flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, sk->sk_protocol, inet_sk_flowi_flags(sk), (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, ireq->ir_loc_addr, ireq->ir_rmt_port, htons(ireq->ir_num), sk->sk_uid); security_req_classify_flow(req, flowi4_to_flowi(fl4)); rt = ip_route_output_flow(net, fl4, sk); if (IS_ERR(rt)) goto no_route; if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) goto route_err; rcu_read_unlock(); return &rt->dst; route_err: ip_rt_put(rt); no_route: rcu_read_unlock(); __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); return NULL; }

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PersonTokensPropCommitsCommitProp
David S. Miller19680.00%111.11%
Eric Dumazet2510.20%444.44%
Christoph Paasch187.35%111.11%
Lorenzo Colitti52.04%222.22%
Julian Anastasov10.41%111.11%
Total245100.00%9100.00%

EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); #if IS_ENABLED(CONFIG_IPV6) #define AF_INET_FAMILY(fam) ((fam) == AF_INET) #else #define AF_INET_FAMILY(fam) true #endif /* Decide when to expire the request and when to resend SYN-ACK */
static inline void syn_ack_recalc(struct request_sock *req, const int thresh, const int max_retries, const u8 rskq_defer_accept, int *expire, int *resend) { if (!rskq_defer_accept) { *expire = req->num_timeout >= thresh; *resend = 1; return; } *expire = req->num_timeout >= thresh && (!inet_rsk(req)->acked || req->num_timeout >= max_retries); /* * Do not resend while waiting for data after ACK, * start to resend on end of deferring period to give * last chance for data or ACK to create established socket. */ *resend