From 39b9722315364121c6e2524515a6e95d52287549 Mon Sep 17 00:00:00 2001 From: Marco Angaroni Date: Tue, 5 Apr 2016 18:26:29 +0200 Subject: [PATCH 1/3] ipvs: handle connections started by real-servers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When using LVS-NAT and SIP persistence-egine over UDP, the following limitations are present with current implementation: 1) To actually have load-balancing based on Call-ID header, you need to use one-packet-scheduling mode. But with one-packet-scheduling the connection is deleted just after packet is forwarded, so SIP responses coming from real-servers do not match any connection and SNAT is not applied. 2) If you do not use "-o" option, IPVS behaves as normal UDP load balancer, so different SIP calls (each one identified by a different Call-ID) coming from the same ip-address/port go to the same real-server. So basically you don’t have load-balancing based on Call-ID as intended. 3) Call-ID is not learned when a new SIP call is started by a real-server (inside-to-outside direction), but only in the outside-to-inside direction. This would be a general problem for all SIP servers acting as Back2BackUserAgent. This patch aims to solve problems 1) and 3) while keeping OPS mode mandatory for SIP-UDP, so that 2) is not a problem anymore. The basic mechanism implemented is to make packets, that do not match any existent connection but come from real-servers, create new connections instead of let them pass without any effect. When such packets pass through ip_vs_out(), if their source ip address and source port match a configured real-server, a new connection is automatically created in the same way as it would have happened if the packet had come from outside-to-inside direction. A new connection template is created too if the virtual-service is persistent and there is no matching connection template found. The new connection automatically created, if the service had "-o" option, is an OPS connection that lasts only the time to forward the packet, just like it happens on the ingress side. The main part of this mechanism is implemented inside a persistent-engine specific callback (at the moment only SIP persistent engine exists) and is triggered only for UDP packets, since connection oriented protocols, by using different set of ports (typically ephemeral ports) to open new outgoing connections, should not need this feature. The following requisites are needed for automatic connection creation; if any is missing the packet simply goes the same way as before. a) virtual-service is not fwmark based (this is because fwmark services do not store address and port of the virtual-service, required to build the connection data). b) virtual-service and real-servers must not have been configured with omitted port (this is again to have all data to create the connection). Signed-off-by: Marco Angaroni Acked-by: Julian Anastasov Signed-off-by: Simon Horman --- include/net/ip_vs.h | 17 ++++ net/netfilter/ipvs/ip_vs_core.c | 154 ++++++++++++++++++++++++++++++ net/netfilter/ipvs/ip_vs_ctl.c | 46 ++++++++- net/netfilter/ipvs/ip_vs_pe_sip.c | 15 +++ 4 files changed, 231 insertions(+), 1 deletion(-) diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index a6cc576fd467f..af4c10ebb2414 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -731,6 +731,12 @@ struct ip_vs_pe { u32 (*hashkey_raw)(const struct ip_vs_conn_param *p, u32 initval, bool inverse); int (*show_pe_data)(const struct ip_vs_conn *cp, char *buf); + /* create connections for real-server outgoing packets */ + struct ip_vs_conn* (*conn_out)(struct ip_vs_service *svc, + struct ip_vs_dest *dest, + struct sk_buff *skb, + const struct ip_vs_iphdr *iph, + __be16 dport, __be16 cport); }; /* The application module object (a.k.a. app incarnation) */ @@ -874,6 +880,7 @@ struct netns_ipvs { /* Service counters */ atomic_t ftpsvc_counter; atomic_t nullsvc_counter; + atomic_t conn_out_counter; #ifdef CONFIG_SYSCTL /* 1/rate drop and drop-entry variables */ @@ -1147,6 +1154,12 @@ static inline int sysctl_cache_bypass(struct netns_ipvs *ipvs) */ const char *ip_vs_proto_name(unsigned int proto); void ip_vs_init_hash_table(struct list_head *table, int rows); +struct ip_vs_conn *ip_vs_new_conn_out(struct ip_vs_service *svc, + struct ip_vs_dest *dest, + struct sk_buff *skb, + const struct ip_vs_iphdr *iph, + __be16 dport, + __be16 cport); #define IP_VS_INIT_HASH_TABLE(t) ip_vs_init_hash_table((t), ARRAY_SIZE((t))) #define IP_VS_APP_TYPE_FTP 1 @@ -1378,6 +1391,10 @@ ip_vs_service_find(struct netns_ipvs *ipvs, int af, __u32 fwmark, __u16 protocol bool ip_vs_has_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol, const union nf_inet_addr *daddr, __be16 dport); +struct ip_vs_dest * +ip_vs_find_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol, + const union nf_inet_addr *daddr, __be16 dport); + int ip_vs_use_count_inc(void); void ip_vs_use_count_dec(void); int ip_vs_register_nl_ioctl(void); diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index b9a4082afa3ab..f3bac2e9a25ab 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -68,6 +68,7 @@ EXPORT_SYMBOL(ip_vs_conn_put); #ifdef CONFIG_IP_VS_DEBUG EXPORT_SYMBOL(ip_vs_get_debug_level); #endif +EXPORT_SYMBOL(ip_vs_new_conn_out); static int ip_vs_net_id __read_mostly; /* netns cnt used for uniqueness */ @@ -1100,6 +1101,143 @@ static inline bool is_new_conn_expected(const struct ip_vs_conn *cp, } } +/* Generic function to create new connections for outgoing RS packets + * + * Pre-requisites for successful connection creation: + * 1) Virtual Service is NOT fwmark based: + * In fwmark-VS actual vaddr and vport are unknown to IPVS + * 2) Real Server and Virtual Service were NOT configured without port: + * This is to allow match of different VS to the same RS ip-addr + */ +struct ip_vs_conn *ip_vs_new_conn_out(struct ip_vs_service *svc, + struct ip_vs_dest *dest, + struct sk_buff *skb, + const struct ip_vs_iphdr *iph, + __be16 dport, + __be16 cport) +{ + struct ip_vs_conn_param param; + struct ip_vs_conn *ct = NULL, *cp = NULL; + const union nf_inet_addr *vaddr, *daddr, *caddr; + union nf_inet_addr snet; + __be16 vport; + unsigned int flags; + + EnterFunction(12); + vaddr = &svc->addr; + vport = svc->port; + daddr = &iph->saddr; + caddr = &iph->daddr; + + /* check pre-requisites are satisfied */ + if (svc->fwmark) + return NULL; + if (!vport || !dport) + return NULL; + + /* for persistent service first create connection template */ + if (svc->flags & IP_VS_SVC_F_PERSISTENT) { + /* apply netmask the same way ingress-side does */ +#ifdef CONFIG_IP_VS_IPV6 + if (svc->af == AF_INET6) + ipv6_addr_prefix(&snet.in6, &caddr->in6, + (__force __u32)svc->netmask); + else +#endif + snet.ip = caddr->ip & svc->netmask; + /* fill params and create template if not existent */ + if (ip_vs_conn_fill_param_persist(svc, skb, iph->protocol, + &snet, 0, vaddr, + vport, ¶m) < 0) + return NULL; + ct = ip_vs_ct_in_get(¶m); + if (!ct) { + ct = ip_vs_conn_new(¶m, dest->af, daddr, dport, + IP_VS_CONN_F_TEMPLATE, dest, 0); + if (!ct) { + kfree(param.pe_data); + return NULL; + } + ct->timeout = svc->timeout; + } else { + kfree(param.pe_data); + } + } + + /* connection flags */ + flags = ((svc->flags & IP_VS_SVC_F_ONEPACKET) && + iph->protocol == IPPROTO_UDP) ? IP_VS_CONN_F_ONE_PACKET : 0; + /* create connection */ + ip_vs_conn_fill_param(svc->ipvs, svc->af, iph->protocol, + caddr, cport, vaddr, vport, ¶m); + cp = ip_vs_conn_new(¶m, dest->af, daddr, dport, flags, dest, 0); + if (!cp) { + if (ct) + ip_vs_conn_put(ct); + return NULL; + } + if (ct) { + ip_vs_control_add(cp, ct); + ip_vs_conn_put(ct); + } + ip_vs_conn_stats(cp, svc); + + /* return connection (will be used to handle outgoing packet) */ + IP_VS_DBG_BUF(6, "New connection RS-initiated:%c c:%s:%u v:%s:%u " + "d:%s:%u conn->flags:%X conn->refcnt:%d\n", + ip_vs_fwd_tag(cp), + IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport), + IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport), + IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport), + cp->flags, atomic_read(&cp->refcnt)); + LeaveFunction(12); + return cp; +} + +/* Handle outgoing packets which are considered requests initiated by + * real servers, so that subsequent responses from external client can be + * routed to the right real server. + * Used also for outgoing responses in OPS mode. + * + * Connection management is handled by persistent-engine specific callback. + */ +static struct ip_vs_conn *__ip_vs_rs_conn_out(unsigned int hooknum, + struct netns_ipvs *ipvs, + int af, struct sk_buff *skb, + const struct ip_vs_iphdr *iph) +{ + struct ip_vs_dest *dest; + struct ip_vs_conn *cp = NULL; + __be16 _ports[2], *pptr; + + if (hooknum == NF_INET_LOCAL_IN) + return NULL; + + pptr = frag_safe_skb_hp(skb, iph->len, + sizeof(_ports), _ports, iph); + if (!pptr) + return NULL; + + rcu_read_lock(); + dest = ip_vs_find_real_service(ipvs, af, iph->protocol, + &iph->saddr, pptr[0]); + if (dest) { + struct ip_vs_service *svc; + struct ip_vs_pe *pe; + + svc = rcu_dereference(dest->svc); + if (svc) { + pe = rcu_dereference(svc->pe); + if (pe && pe->conn_out) + cp = pe->conn_out(svc, dest, skb, iph, + pptr[0], pptr[1]); + } + } + rcu_read_unlock(); + + return cp; +} + /* Handle response packets: rewrite addresses and send away... */ static unsigned int @@ -1245,6 +1383,22 @@ ip_vs_out(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, in if (likely(cp)) return handle_response(af, skb, pd, cp, &iph, hooknum); + + /* Check for real-server-started requests */ + if (atomic_read(&ipvs->conn_out_counter)) { + /* Currently only for UDP: + * connection oriented protocols typically use + * ephemeral ports for outgoing connections, so + * related incoming responses would not match any VS + */ + if (pp->protocol == IPPROTO_UDP) { + cp = __ip_vs_rs_conn_out(hooknum, ipvs, af, skb, &iph); + if (likely(cp)) + return handle_response(af, skb, pd, cp, &iph, + hooknum); + } + } + if (sysctl_nat_icmp_send(ipvs) && (pp->protocol == IPPROTO_TCP || pp->protocol == IPPROTO_UDP || diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 404b2a4f4b5be..6794391c5a328 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -567,6 +567,36 @@ bool ip_vs_has_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol, return false; } +/* Find real service record by . + * In case of multiple records with the same , only + * the first found record is returned. + * + * To be called under RCU lock. + */ +struct ip_vs_dest *ip_vs_find_real_service(struct netns_ipvs *ipvs, int af, + __u16 protocol, + const union nf_inet_addr *daddr, + __be16 dport) +{ + unsigned int hash; + struct ip_vs_dest *dest; + + /* Check for "full" addressed entries */ + hash = ip_vs_rs_hashkey(af, daddr, dport); + + hlist_for_each_entry_rcu(dest, &ipvs->rs_table[hash], d_list) { + if (dest->port == dport && + dest->af == af && + ip_vs_addr_equal(af, &dest->addr, daddr) && + (dest->protocol == protocol || dest->vfwmark)) { + /* HIT */ + return dest; + } + } + + return NULL; +} + /* Lookup destination by {addr,port} in the given service * Called under RCU lock. */ @@ -1253,6 +1283,8 @@ ip_vs_add_service(struct netns_ipvs *ipvs, struct ip_vs_service_user_kern *u, atomic_inc(&ipvs->ftpsvc_counter); else if (svc->port == 0) atomic_inc(&ipvs->nullsvc_counter); + if (svc->pe && svc->pe->conn_out) + atomic_inc(&ipvs->conn_out_counter); ip_vs_start_estimator(ipvs, &svc->stats); @@ -1293,6 +1325,7 @@ ip_vs_edit_service(struct ip_vs_service *svc, struct ip_vs_service_user_kern *u) struct ip_vs_scheduler *sched = NULL, *old_sched; struct ip_vs_pe *pe = NULL, *old_pe = NULL; int ret = 0; + bool new_pe_conn_out, old_pe_conn_out; /* * Lookup the scheduler, by 'u->sched_name' @@ -1355,8 +1388,16 @@ ip_vs_edit_service(struct ip_vs_service *svc, struct ip_vs_service_user_kern *u) svc->netmask = u->netmask; old_pe = rcu_dereference_protected(svc->pe, 1); - if (pe != old_pe) + if (pe != old_pe) { rcu_assign_pointer(svc->pe, pe); + /* check for optional methods in new pe */ + new_pe_conn_out = (pe && pe->conn_out) ? true : false; + old_pe_conn_out = (old_pe && old_pe->conn_out) ? true : false; + if (new_pe_conn_out && !old_pe_conn_out) + atomic_inc(&svc->ipvs->conn_out_counter); + if (old_pe_conn_out && !new_pe_conn_out) + atomic_dec(&svc->ipvs->conn_out_counter); + } out: ip_vs_scheduler_put(old_sched); @@ -1389,6 +1430,8 @@ static void __ip_vs_del_service(struct ip_vs_service *svc, bool cleanup) /* Unbind persistence engine, keep svc->pe */ old_pe = rcu_dereference_protected(svc->pe, 1); + if (old_pe && old_pe->conn_out) + atomic_dec(&ipvs->conn_out_counter); ip_vs_pe_put(old_pe); /* @@ -3957,6 +4000,7 @@ int __net_init ip_vs_control_net_init(struct netns_ipvs *ipvs) (unsigned long) ipvs); atomic_set(&ipvs->ftpsvc_counter, 0); atomic_set(&ipvs->nullsvc_counter, 0); + atomic_set(&ipvs->conn_out_counter, 0); /* procfs stats */ ipvs->tot_stats.cpustats = alloc_percpu(struct ip_vs_cpu_stats); diff --git a/net/netfilter/ipvs/ip_vs_pe_sip.c b/net/netfilter/ipvs/ip_vs_pe_sip.c index 0a6eb5c0d9e9c..d07ef9e31c12d 100644 --- a/net/netfilter/ipvs/ip_vs_pe_sip.c +++ b/net/netfilter/ipvs/ip_vs_pe_sip.c @@ -143,6 +143,20 @@ static int ip_vs_sip_show_pe_data(const struct ip_vs_conn *cp, char *buf) return cp->pe_data_len; } +static struct ip_vs_conn * +ip_vs_sip_conn_out(struct ip_vs_service *svc, + struct ip_vs_dest *dest, + struct sk_buff *skb, + const struct ip_vs_iphdr *iph, + __be16 dport, + __be16 cport) +{ + if (likely(iph->protocol == IPPROTO_UDP)) + return ip_vs_new_conn_out(svc, dest, skb, iph, dport, cport); + /* currently no need to handle other than UDP */ + return NULL; +} + static struct ip_vs_pe ip_vs_sip_pe = { .name = "sip", @@ -153,6 +167,7 @@ static struct ip_vs_pe ip_vs_sip_pe = .ct_match = ip_vs_sip_ct_match, .hashkey_raw = ip_vs_sip_hashkey_raw, .show_pe_data = ip_vs_sip_show_pe_data, + .conn_out = ip_vs_sip_conn_out, }; static int __init ip_vs_sip_init(void) From 013b042465d3fefef84b4b87947747eda08277e2 Mon Sep 17 00:00:00 2001 From: Marco Angaroni Date: Tue, 5 Apr 2016 18:26:52 +0200 Subject: [PATCH 2/3] ipvs: optimize release of connections in OPS mode One-packet-scheduling is the most expensive mode in IPVS from performance point of view: for each packet to be processed a new connection data structure is created and, after packet is sent, deleted by starting a new timer set to expire immediately. SIP persistent-engine needs OPS mode to have Call-ID based load balancing, so OPS mode performance has negative impact in SIP protocol load balancing. This patch aims to improve performance of OPS mode by means of the following changes in the release mechanism of OPS connections: a) call expire callback ip_vs_conn_expire() directly instead of starting a timer programmed to fire immediately. b) avoid call_rcu() overhead inside expire callback, since OPS connection are not inserted in the hash-table and last just the time to process the packet, hence there is no concurrent access to such data structures. Signed-off-by: Marco Angaroni Acked-by: Julian Anastasov Signed-off-by: Simon Horman --- net/netfilter/ipvs/ip_vs_conn.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c index 85ca189bdc3d2..dd75d4120099b 100644 --- a/net/netfilter/ipvs/ip_vs_conn.c +++ b/net/netfilter/ipvs/ip_vs_conn.c @@ -104,6 +104,7 @@ static inline void ct_write_unlock_bh(unsigned int key) spin_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l); } +static void ip_vs_conn_expire(unsigned long data); /* * Returns hash value for IPVS connection entry @@ -453,10 +454,16 @@ ip_vs_conn_out_get_proto(struct netns_ipvs *ipvs, int af, } EXPORT_SYMBOL_GPL(ip_vs_conn_out_get_proto); +static void __ip_vs_conn_put_notimer(struct ip_vs_conn *cp) +{ + __ip_vs_conn_put(cp); + ip_vs_conn_expire((unsigned long)cp); +} + /* * Put back the conn and restart its timer with its timeout */ -void ip_vs_conn_put(struct ip_vs_conn *cp) +static void __ip_vs_conn_put_timer(struct ip_vs_conn *cp) { unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ? 0 : cp->timeout; @@ -465,6 +472,16 @@ void ip_vs_conn_put(struct ip_vs_conn *cp) __ip_vs_conn_put(cp); } +void ip_vs_conn_put(struct ip_vs_conn *cp) +{ + if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) && + (atomic_read(&cp->refcnt) == 1) && + !timer_pending(&cp->timer)) + /* expire connection immediately */ + __ip_vs_conn_put_notimer(cp); + else + __ip_vs_conn_put_timer(cp); +} /* * Fill a no_client_port connection with a client port number @@ -834,7 +851,10 @@ static void ip_vs_conn_expire(unsigned long data) ip_vs_unbind_dest(cp); if (cp->flags & IP_VS_CONN_F_NO_CPORT) atomic_dec(&ip_vs_conn_no_cport_cnt); - call_rcu(&cp->rcu_head, ip_vs_conn_rcu_free); + if (cp->flags & IP_VS_CONN_F_ONE_PACKET) + ip_vs_conn_rcu_free(&cp->rcu_head); + else + call_rcu(&cp->rcu_head, ip_vs_conn_rcu_free); atomic_dec(&ipvs->conn_count); return; } @@ -850,7 +870,7 @@ static void ip_vs_conn_expire(unsigned long data) if (ipvs->sync_state & IP_VS_STATE_MASTER) ip_vs_sync_conn(ipvs, cp, sysctl_sync_threshold(ipvs)); - ip_vs_conn_put(cp); + __ip_vs_conn_put_timer(cp); } /* Modify timer, so that it expires as soon as possible. From 8fb04d9fc70a67ccabf71dbabf92d7f6fca64a16 Mon Sep 17 00:00:00 2001 From: Marco Angaroni Date: Sat, 9 Apr 2016 14:14:23 +0200 Subject: [PATCH 3/3] ipvs: don't alter conntrack in OPS mode When using OPS mode in conjunction with SIP persistent-engine, packets originating from the same ip-address/port could be balanced to different real servers, and (to properly handle SIP responses) OPS connections are created in the in-out direction too, where ip_vs_update_conntrack() is called to modify the reply tuple. As a result, there can be collision of conntrack tuples, causing random packet drops, as explained below: conntrack1: orig=CIP->VIP, reply=RIP1->CIP conntrack2: orig=RIP2->CIP, reply=CIP->VIP Tuple CIP->VIP is both in orig of conntrack1 and reply of conntrack2. The collision triggers packet drop inside nf_conntrack processing. In addition, the current implementation deletes the conntrack object at every expire of an OPS connection (once every forwarded packet), to have it recreated from scratch at next packet traversing IPVS. Since in OPS mode, by definition, we don't expect any associated response, the choices implemented in this patch are: a) don't call nf_conntrack_alter_reply() for OPS connections inside ip_vs_update_conntrack(). b) don't delete the conntrack object at OPS connection expire. The result is that created conntrack objects for each tuple CIP->VIP, RIP-N->CIP, etc. are left in UNREPLIED state and not modified by IPVS OPS connection management. This eliminates packet drops and leaves a single conntrack object for each tuple packets are sent from. Signed-off-by: Marco Angaroni Signed-off-by: Julian Anastasov Signed-off-by: Simon Horman --- net/netfilter/ipvs/ip_vs_conn.c | 3 ++- net/netfilter/ipvs/ip_vs_nfct.c | 4 ++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c index dd75d4120099b..292365ffa4f02 100644 --- a/net/netfilter/ipvs/ip_vs_conn.c +++ b/net/netfilter/ipvs/ip_vs_conn.c @@ -836,7 +836,8 @@ static void ip_vs_conn_expire(unsigned long data) if (cp->control) ip_vs_control_del(cp); - if (cp->flags & IP_VS_CONN_F_NFCT) { + if ((cp->flags & IP_VS_CONN_F_NFCT) && + !(cp->flags & IP_VS_CONN_F_ONE_PACKET)) { /* Do not access conntracks during subsys cleanup * because nf_conntrack_find_get can not be used after * conntrack cleanup for the net. diff --git a/net/netfilter/ipvs/ip_vs_nfct.c b/net/netfilter/ipvs/ip_vs_nfct.c index 30434fb133df6..f04fd8df210b4 100644 --- a/net/netfilter/ipvs/ip_vs_nfct.c +++ b/net/netfilter/ipvs/ip_vs_nfct.c @@ -93,6 +93,10 @@ ip_vs_update_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp, int outin) if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) return; + /* Never alter conntrack for OPS conns (no reply is expected) */ + if (cp->flags & IP_VS_CONN_F_ONE_PACKET) + return; + /* Alter reply only in original direction */ if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) return;