diff options
Diffstat (limited to 'net/ipv4/icmp.c')
-rw-r--r-- | net/ipv4/icmp.c | 258 |
1 files changed, 140 insertions, 118 deletions
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index e63a3bf99617..717cb7d3607a 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -92,6 +92,10 @@ #include <net/inet_common.h> #include <net/ip_fib.h> #include <net/l3mdev.h> +#include <net/addrconf.h> +#include <net/inet_dscp.h> +#define CREATE_TRACE_POINTS +#include <trace/events/icmp.h> /* * Build xmit assembly blocks @@ -217,61 +221,56 @@ static inline void icmp_xmit_unlock(struct sock *sk) spin_unlock(&sk->sk_lock.slock); } -int sysctl_icmp_msgs_per_sec __read_mostly = 1000; -int sysctl_icmp_msgs_burst __read_mostly = 50; - -static struct { - spinlock_t lock; - u32 credit; - u32 stamp; -} icmp_global = { - .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), -}; - /** * icmp_global_allow - Are we allowed to send one more ICMP message ? + * @net: network namespace * * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec. * Returns false if we reached the limit and can not send another packet. - * Note: called with BH disabled + * Works in tandem with icmp_global_consume(). */ -bool icmp_global_allow(void) +bool icmp_global_allow(struct net *net) { - u32 credit, delta, incr = 0, now = (u32)jiffies; - bool rc = false; + u32 delta, now, oldstamp; + int incr, new, old; - /* Check if token bucket is empty and cannot be refilled - * without taking the spinlock. The READ_ONCE() are paired - * with the following WRITE_ONCE() in this same function. + /* Note: many cpus could find this condition true. + * Then later icmp_global_consume() could consume more credits, + * this is an acceptable race. */ - if (!READ_ONCE(icmp_global.credit)) { - delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ); - if (delta < HZ / 50) - return false; - } + if (atomic_read(&net->ipv4.icmp_global_credit) > 0) + return true; - spin_lock(&icmp_global.lock); - delta = min_t(u32, now - icmp_global.stamp, HZ); - if (delta >= HZ / 50) { - incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; - if (incr) - WRITE_ONCE(icmp_global.stamp, now); - } - credit = min_t(u32, icmp_global.credit + incr, - READ_ONCE(sysctl_icmp_msgs_burst)); - if (credit) { - /* We want to use a credit of one in average, but need to randomize - * it for security reasons. - */ - credit = max_t(int, credit - get_random_u32_below(3), 0); - rc = true; + now = jiffies; + oldstamp = READ_ONCE(net->ipv4.icmp_global_stamp); + delta = min_t(u32, now - oldstamp, HZ); + if (delta < HZ / 50) + return false; + + incr = READ_ONCE(net->ipv4.sysctl_icmp_msgs_per_sec) * delta / HZ; + if (!incr) + return false; + + if (cmpxchg(&net->ipv4.icmp_global_stamp, oldstamp, now) == oldstamp) { + old = atomic_read(&net->ipv4.icmp_global_credit); + do { + new = min(old + incr, READ_ONCE(net->ipv4.sysctl_icmp_msgs_burst)); + } while (!atomic_try_cmpxchg(&net->ipv4.icmp_global_credit, &old, new)); } - WRITE_ONCE(icmp_global.credit, credit); - spin_unlock(&icmp_global.lock); - return rc; + return true; } EXPORT_SYMBOL(icmp_global_allow); +void icmp_global_consume(struct net *net) +{ + int credits = get_random_u32_below(3); + + /* Note: this might make icmp_global.credit negative. */ + if (credits) + atomic_sub(credits, &net->ipv4.icmp_global_credit); +} +EXPORT_SYMBOL(icmp_global_consume); + static bool icmpv4_mask_allow(struct net *net, int type, int code) { if (type > NR_ICMP_TYPES) @@ -288,14 +287,16 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code) return false; } -static bool icmpv4_global_allow(struct net *net, int type, int code) +static bool icmpv4_global_allow(struct net *net, int type, int code, + bool *apply_ratelimit) { if (icmpv4_mask_allow(net, type, code)) return true; - if (icmp_global_allow()) + if (icmp_global_allow(net)) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -305,29 +306,31 @@ static bool icmpv4_global_allow(struct net *net, int type, int code) */ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, - struct flowi4 *fl4, int type, int code) + struct flowi4 *fl4, int type, int code, + bool apply_ratelimit) { struct dst_entry *dst = &rt->dst; struct inet_peer *peer; bool rc = true; - int vif; - if (icmpv4_mask_allow(net, type, code)) - goto out; + if (!apply_ratelimit) + return true; /* No rate limit on loopback */ if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) goto out; - vif = l3mdev_master_ifindex(dst->dev); - peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1); + rcu_read_lock(); + peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, + l3mdev_master_ifindex_rcu(dst->dev)); rc = inet_peer_xrlim_allow(peer, READ_ONCE(net->ipv4.sysctl_icmp_ratelimit)); - if (peer) - inet_putpeer(peer); + rcu_read_unlock(); out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); + else + icmp_global_consume(net); return rc; } @@ -396,12 +399,12 @@ static void icmp_push_reply(struct sock *sk, static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) { - struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); - struct net *net = dev_net(rt->dst.dev); + struct net *net = dev_net_rcu(rt->dst.dev); + bool apply_ratelimit = false; + struct ipcm_cookie ipc; struct flowi4 fl4; struct sock *sk; - struct inet_sock *inet; __be32 daddr, saddr; u32 mark = IP4_REPLY_MARK(net, skb->mark); int type = icmp_param->data.icmph.type; @@ -410,22 +413,21 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb)) return; - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); - /* global icmp_msgs_per_sec */ - if (!icmpv4_global_allow(net, type, code)) + /* is global icmp_msgs_per_sec exhausted ? */ + if (!icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); if (!sk) goto out_bh_enable; - inet = inet_sk(sk); icmp_param->data.icmph.checksum = 0; ipcm_init(&ipc); - inet->tos = ip_hdr(skb)->tos; + ipc.tos = ip_hdr(skb)->tos; ipc.sockc.mark = mark; daddr = ipc.addr = ip_hdr(skb)->saddr; saddr = fib_compute_spec_dst(skb); @@ -440,14 +442,14 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) fl4.saddr = saddr; fl4.flowi4_mark = mark; fl4.flowi4_uid = sock_net_uid(net, NULL); - fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); + fl4.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(ip_hdr(skb))); fl4.flowi4_proto = IPPROTO_ICMP; fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev); security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4)); rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) goto out_unlock; - if (icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt); ip_rt_put(rt); out_unlock: @@ -473,15 +475,14 @@ static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb) return route_lookup_dev; } -static struct rtable *icmp_route_lookup(struct net *net, - struct flowi4 *fl4, +static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4, struct sk_buff *skb_in, - const struct iphdr *iph, - __be32 saddr, u8 tos, u32 mark, - int type, int code, - struct icmp_bxm *param) + const struct iphdr *iph, __be32 saddr, + dscp_t dscp, u32 mark, int type, + int code, struct icmp_bxm *param) { struct net_device *route_lookup_dev; + struct dst_entry *dst, *dst2; struct rtable *rt, *rt2; struct flowi4 fl4_dec; int err; @@ -492,7 +493,7 @@ static struct rtable *icmp_route_lookup(struct net *net, fl4->saddr = saddr; fl4->flowi4_mark = mark; fl4->flowi4_uid = sock_net_uid(net, NULL); - fl4->flowi4_tos = RT_TOS(tos); + fl4->flowi4_tos = inet_dscp_to_dsfield(dscp); fl4->flowi4_proto = IPPROTO_ICMP; fl4->fl4_icmp_type = type; fl4->fl4_icmp_code = code; @@ -507,16 +508,20 @@ static struct rtable *icmp_route_lookup(struct net *net, /* No need to clone since we're just using its address. */ rt2 = rt; - rt = (struct rtable *) xfrm_lookup(net, &rt->dst, - flowi4_to_flowi(fl4), NULL, 0); - if (!IS_ERR(rt)) { + dst = xfrm_lookup(net, &rt->dst, + flowi4_to_flowi(fl4), NULL, 0); + rt = dst_rtable(dst); + if (!IS_ERR(dst)) { if (rt != rt2) return rt; - } else if (PTR_ERR(rt) == -EPERM) { + if (inet_addr_type_dev_table(net, route_lookup_dev, + fl4->daddr) == RTN_LOCAL) + return rt; + } else if (PTR_ERR(dst) == -EPERM) { rt = NULL; - } else + } else { return rt; - + } err = xfrm_decode_session_reverse(net, skb_in, flowi4_to_flowi(&fl4_dec), AF_INET); if (err) goto relookup_failed; @@ -540,7 +545,7 @@ static struct rtable *icmp_route_lookup(struct net *net, orefdst = skb_in->_skb_refdst; /* save old refdst */ skb_dst_set(skb_in, NULL); err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr, - RT_TOS(tos), rt2->dst.dev); + dscp, rt2->dst.dev) ? -EINVAL : 0; dst_release(&rt2->dst); rt2 = skb_rtable(skb_in); @@ -550,19 +555,19 @@ static struct rtable *icmp_route_lookup(struct net *net, if (err) goto relookup_failed; - rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst, - flowi4_to_flowi(&fl4_dec), NULL, - XFRM_LOOKUP_ICMP); - if (!IS_ERR(rt2)) { + dst2 = xfrm_lookup(net, &rt2->dst, flowi4_to_flowi(&fl4_dec), NULL, + XFRM_LOOKUP_ICMP); + rt2 = dst_rtable(dst2); + if (!IS_ERR(dst2)) { dst_release(&rt->dst); memcpy(fl4, &fl4_dec, sizeof(*fl4)); rt = rt2; - } else if (PTR_ERR(rt2) == -EPERM) { + } else if (PTR_ERR(dst2) == -EPERM) { if (rt) dst_release(&rt->dst); return rt2; } else { - err = PTR_ERR(rt2); + err = PTR_ERR(dst2); goto relookup_failed; } return rt; @@ -591,6 +596,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, int room; struct icmp_bxm icmp_param; struct rtable *rt = skb_rtable(skb_in); + bool apply_ratelimit = false; struct ipcm_cookie ipc; struct flowi4 fl4; __be32 saddr; @@ -600,12 +606,14 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, struct sock *sk; if (!rt) - goto out; + return; + + rcu_read_lock(); if (rt->dst.dev) - net = dev_net(rt->dst.dev); + net = dev_net_rcu(rt->dst.dev); else if (skb_in->dev) - net = dev_net(skb_in->dev); + net = dev_net_rcu(skb_in->dev); else goto out; @@ -672,7 +680,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, } } - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless @@ -680,7 +688,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow) */ if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) && - !icmpv4_global_allow(net, type, code)) + !icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -727,19 +735,20 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, icmp_param.data.icmph.checksum = 0; icmp_param.skb = skb_in; icmp_param.offset = skb_network_offset(skb_in); - inet_sk(sk)->tos = tos; ipcm_init(&ipc); + ipc.tos = tos; ipc.addr = iph->saddr; ipc.opt = &icmp_param.replyopts.opt; ipc.sockc.mark = mark; - rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark, - type, code, &icmp_param); + rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, + inet_dsfield_to_dscp(tos), mark, type, code, + &icmp_param); if (IS_ERR(rt)) goto out_unlock; /* peer icmp_ratelimit */ - if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) goto ende; /* RFC says return as much as we can without exceeding 576 bytes. */ @@ -767,6 +776,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, if (!fl4.saddr) fl4.saddr = htonl(INADDR_DUMMY); + trace_icmp_send(skb_in, type, code); + icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt); ende: ip_rt_put(rt); @@ -774,7 +785,8 @@ out_unlock: icmp_xmit_unlock(sk); out_bh_enable: local_bh_enable(); -out:; +out: + rcu_read_unlock(); } EXPORT_SYMBOL(__icmp_send); @@ -823,7 +835,7 @@ static void icmp_socket_deliver(struct sk_buff *skb, u32 info) * avoid additional coding at protocol handlers. */ if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) { - __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); return; } @@ -857,7 +869,7 @@ static enum skb_drop_reason icmp_unreach(struct sk_buff *skb) struct net *net; u32 info = 0; - net = dev_net(skb_dst(skb)->dev); + net = dev_net_rcu(skb_dst(skb)->dev); /* * Incomplete header ? @@ -968,7 +980,7 @@ out_err: static enum skb_drop_reason icmp_redirect(struct sk_buff *skb) { if (skb->len < sizeof(struct iphdr)) { - __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); return SKB_DROP_REASON_PKT_TOO_SMALL; } @@ -1000,7 +1012,7 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb) struct icmp_bxm icmp_param; struct net *net; - net = dev_net(skb_dst(skb)->dev); + net = dev_net_rcu(skb_dst(skb)->dev); /* should there be an ICMP stat for ignored echos? */ if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all)) return SKB_NOT_DROPPED_YET; @@ -1029,9 +1041,11 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb) bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) { + struct net *net = dev_net_rcu(skb->dev); struct icmp_ext_hdr *ext_hdr, _ext_hdr; struct icmp_ext_echo_iio *iio, _iio; - struct net *net = dev_net(skb->dev); + struct inet6_dev *in6_dev; + struct in_device *in_dev; struct net_device *dev; char buff[IFNAMSIZ]; u16 ident_len; @@ -1115,10 +1129,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) /* Fill bits in reply message */ if (dev->flags & IFF_UP) status |= ICMP_EXT_ECHOREPLY_ACTIVE; - if (__in_dev_get_rcu(dev) && __in_dev_get_rcu(dev)->ifa_list) + + in_dev = __in_dev_get_rcu(dev); + if (in_dev && rcu_access_pointer(in_dev->ifa_list)) status |= ICMP_EXT_ECHOREPLY_IPV4; - if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list)) + + in6_dev = __in6_dev_get(dev); + if (in6_dev && !list_empty(&in6_dev->addr_list)) status |= ICMP_EXT_ECHOREPLY_IPV6; + dev_put(dev); icmphdr->un.echo.sequence |= htons(status); return true; @@ -1163,7 +1182,7 @@ static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb) return SKB_NOT_DROPPED_YET; out_err: - __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb_dst(skb)->dev), ICMP_MIB_INERRORS); return SKB_DROP_REASON_PKT_TOO_SMALL; } @@ -1180,7 +1199,7 @@ int icmp_rcv(struct sk_buff *skb) { enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; struct rtable *rt = skb_rtable(skb); - struct net *net = dev_net(rt->dst.dev); + struct net *net = dev_net_rcu(rt->dst.dev); struct icmphdr *icmph; if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { @@ -1229,22 +1248,6 @@ int icmp_rcv(struct sk_buff *skb) goto reason_check; } - if (icmph->type == ICMP_EXT_ECHOREPLY) { - reason = ping_rcv(skb); - goto reason_check; - } - - /* - * 18 is the highest 'known' ICMP type. Anything else is a mystery - * - * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently - * discarded. - */ - if (icmph->type > NR_ICMP_TYPES) { - reason = SKB_DROP_REASON_UNHANDLED_PROTO; - goto error; - } - /* * Parse the ICMP message */ @@ -1271,6 +1274,23 @@ int icmp_rcv(struct sk_buff *skb) } } + if (icmph->type == ICMP_EXT_ECHOREPLY || + icmph->type == ICMP_ECHOREPLY) { + reason = ping_rcv(skb); + return reason ? NET_RX_DROP : NET_RX_SUCCESS; + } + + /* + * 18 is the highest 'known' ICMP type. Anything else is a mystery + * + * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently + * discarded. + */ + if (icmph->type > NR_ICMP_TYPES) { + reason = SKB_DROP_REASON_UNHANDLED_PROTO; + goto error; + } + reason = icmp_pointers[icmph->type].handler(skb); reason_check: if (!reason) { @@ -1353,9 +1373,9 @@ int icmp_err(struct sk_buff *skb, u32 info) struct iphdr *iph = (struct iphdr *)skb->data; int offset = iph->ihl<<2; struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset); + struct net *net = dev_net_rcu(skb->dev); int type = icmp_hdr(skb)->type; int code = icmp_hdr(skb)->code; - struct net *net = dev_net(skb->dev); /* * Use ping_err to handle all icmp errors except those @@ -1473,6 +1493,8 @@ static int __net_init icmp_sk_init(struct net *net) net->ipv4.sysctl_icmp_ratelimit = 1 * HZ; net->ipv4.sysctl_icmp_ratemask = 0x1818; net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0; + net->ipv4.sysctl_icmp_msgs_per_sec = 1000; + net->ipv4.sysctl_icmp_msgs_burst = 50; return 0; } |