| /* |
| * ip_vs_proto_udp.c: UDP load balancing support for IPVS |
| * |
| * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
| * Julian Anastasov <ja@ssi.bg> |
| * |
| * 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. |
| * |
| * Changes: Hans Schillstrom <hans.schillstrom@ericsson.com> |
| * Network name space (netns) aware. |
| * |
| */ |
| |
| #define KMSG_COMPONENT "IPVS" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #include <linux/kernel.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/udp.h> |
| |
| #include <net/ip_vs.h> |
| #include <net/ip.h> |
| #include <net/ip6_checksum.h> |
| |
| static int |
| udp_conn_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb, |
| struct ip_vs_proto_data *pd, |
| int *verdict, struct ip_vs_conn **cpp, |
| struct ip_vs_iphdr *iph) |
| { |
| struct ip_vs_service *svc; |
| struct udphdr _udph, *uh; |
| __be16 _ports[2], *ports = NULL; |
| |
| if (likely(!ip_vs_iph_icmp(iph))) { |
| /* IPv6 fragments, only first fragment will hit this */ |
| uh = skb_header_pointer(skb, iph->len, sizeof(_udph), &_udph); |
| if (uh) |
| ports = &uh->source; |
| } else { |
| ports = skb_header_pointer( |
| skb, iph->len, sizeof(_ports), &_ports); |
| } |
| |
| if (!ports) { |
| *verdict = NF_DROP; |
| return 0; |
| } |
| |
| if (likely(!ip_vs_iph_inverse(iph))) |
| svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol, |
| &iph->daddr, ports[1]); |
| else |
| svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol, |
| &iph->saddr, ports[0]); |
| |
| if (svc) { |
| int ignored; |
| |
| if (ip_vs_todrop(ipvs)) { |
| /* |
| * It seems that we are very loaded. |
| * We have to drop this packet :( |
| */ |
| *verdict = NF_DROP; |
| return 0; |
| } |
| |
| /* |
| * Let the virtual server select a real server for the |
| * incoming connection, and create a connection entry. |
| */ |
| *cpp = ip_vs_schedule(svc, skb, pd, &ignored, iph); |
| if (!*cpp && ignored <= 0) { |
| if (!ignored) |
| *verdict = ip_vs_leave(svc, skb, pd, iph); |
| else |
| *verdict = NF_DROP; |
| return 0; |
| } |
| } |
| /* NF_ACCEPT */ |
| return 1; |
| } |
| |
| |
| static inline void |
| udp_fast_csum_update(int af, struct udphdr *uhdr, |
| const union nf_inet_addr *oldip, |
| const union nf_inet_addr *newip, |
| __be16 oldport, __be16 newport) |
| { |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (af == AF_INET6) |
| uhdr->check = |
| csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6, |
| ip_vs_check_diff2(oldport, newport, |
| ~csum_unfold(uhdr->check)))); |
| else |
| #endif |
| uhdr->check = |
| csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip, |
| ip_vs_check_diff2(oldport, newport, |
| ~csum_unfold(uhdr->check)))); |
| if (!uhdr->check) |
| uhdr->check = CSUM_MANGLED_0; |
| } |
| |
| static inline void |
| udp_partial_csum_update(int af, struct udphdr *uhdr, |
| const union nf_inet_addr *oldip, |
| const union nf_inet_addr *newip, |
| __be16 oldlen, __be16 newlen) |
| { |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (af == AF_INET6) |
| uhdr->check = |
| ~csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6, |
| ip_vs_check_diff2(oldlen, newlen, |
| csum_unfold(uhdr->check)))); |
| else |
| #endif |
| uhdr->check = |
| ~csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip, |
| ip_vs_check_diff2(oldlen, newlen, |
| csum_unfold(uhdr->check)))); |
| } |
| |
| |
| static int |
| udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp, |
| struct ip_vs_conn *cp, struct ip_vs_iphdr *iph) |
| { |
| struct udphdr *udph; |
| unsigned int udphoff = iph->len; |
| int oldlen; |
| int payload_csum = 0; |
| |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (cp->af == AF_INET6 && iph->fragoffs) |
| return 1; |
| #endif |
| oldlen = skb->len - udphoff; |
| |
| /* csum_check requires unshared skb */ |
| if (!skb_make_writable(skb, udphoff+sizeof(*udph))) |
| return 0; |
| |
| if (unlikely(cp->app != NULL)) { |
| int ret; |
| |
| /* Some checks before mangling */ |
| if (pp->csum_check && !pp->csum_check(cp->af, skb, pp)) |
| return 0; |
| |
| /* |
| * Call application helper if needed |
| */ |
| if (!(ret = ip_vs_app_pkt_out(cp, skb, iph))) |
| return 0; |
| /* ret=2: csum update is needed after payload mangling */ |
| if (ret == 1) |
| oldlen = skb->len - udphoff; |
| else |
| payload_csum = 1; |
| } |
| |
| udph = (void *)skb_network_header(skb) + udphoff; |
| udph->source = cp->vport; |
| |
| /* |
| * Adjust UDP checksums |
| */ |
| if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| udp_partial_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr, |
| htons(oldlen), |
| htons(skb->len - udphoff)); |
| } else if (!payload_csum && (udph->check != 0)) { |
| /* Only port and addr are changed, do fast csum update */ |
| udp_fast_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr, |
| cp->dport, cp->vport); |
| if (skb->ip_summed == CHECKSUM_COMPLETE) |
| skb->ip_summed = (cp->app && pp->csum_check) ? |
| CHECKSUM_UNNECESSARY : CHECKSUM_NONE; |
| } else { |
| /* full checksum calculation */ |
| udph->check = 0; |
| skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0); |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (cp->af == AF_INET6) |
| udph->check = csum_ipv6_magic(&cp->vaddr.in6, |
| &cp->caddr.in6, |
| skb->len - udphoff, |
| cp->protocol, skb->csum); |
| else |
| #endif |
| udph->check = csum_tcpudp_magic(cp->vaddr.ip, |
| cp->caddr.ip, |
| skb->len - udphoff, |
| cp->protocol, |
| skb->csum); |
| if (udph->check == 0) |
| udph->check = CSUM_MANGLED_0; |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n", |
| pp->name, udph->check, |
| (char*)&(udph->check) - (char*)udph); |
| } |
| return 1; |
| } |
| |
| |
| static int |
| udp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp, |
| struct ip_vs_conn *cp, struct ip_vs_iphdr *iph) |
| { |
| struct udphdr *udph; |
| unsigned int udphoff = iph->len; |
| int oldlen; |
| int payload_csum = 0; |
| |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (cp->af == AF_INET6 && iph->fragoffs) |
| return 1; |
| #endif |
| oldlen = skb->len - udphoff; |
| |
| /* csum_check requires unshared skb */ |
| if (!skb_make_writable(skb, udphoff+sizeof(*udph))) |
| return 0; |
| |
| if (unlikely(cp->app != NULL)) { |
| int ret; |
| |
| /* Some checks before mangling */ |
| if (pp->csum_check && !pp->csum_check(cp->af, skb, pp)) |
| return 0; |
| |
| /* |
| * Attempt ip_vs_app call. |
| * It will fix ip_vs_conn |
| */ |
| if (!(ret = ip_vs_app_pkt_in(cp, skb, iph))) |
| return 0; |
| /* ret=2: csum update is needed after payload mangling */ |
| if (ret == 1) |
| oldlen = skb->len - udphoff; |
| else |
| payload_csum = 1; |
| } |
| |
| udph = (void *)skb_network_header(skb) + udphoff; |
| udph->dest = cp->dport; |
| |
| /* |
| * Adjust UDP checksums |
| */ |
| if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| udp_partial_csum_update(cp->af, udph, &cp->vaddr, &cp->daddr, |
| htons(oldlen), |
| htons(skb->len - udphoff)); |
| } else if (!payload_csum && (udph->check != 0)) { |
| /* Only port and addr are changed, do fast csum update */ |
| udp_fast_csum_update(cp->af, udph, &cp->vaddr, &cp->daddr, |
| cp->vport, cp->dport); |
| if (skb->ip_summed == CHECKSUM_COMPLETE) |
| skb->ip_summed = (cp->app && pp->csum_check) ? |
| CHECKSUM_UNNECESSARY : CHECKSUM_NONE; |
| } else { |
| /* full checksum calculation */ |
| udph->check = 0; |
| skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0); |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (cp->af == AF_INET6) |
| udph->check = csum_ipv6_magic(&cp->caddr.in6, |
| &cp->daddr.in6, |
| skb->len - udphoff, |
| cp->protocol, skb->csum); |
| else |
| #endif |
| udph->check = csum_tcpudp_magic(cp->caddr.ip, |
| cp->daddr.ip, |
| skb->len - udphoff, |
| cp->protocol, |
| skb->csum); |
| if (udph->check == 0) |
| udph->check = CSUM_MANGLED_0; |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| } |
| return 1; |
| } |
| |
| |
| static int |
| udp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp) |
| { |
| struct udphdr _udph, *uh; |
| unsigned int udphoff; |
| |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (af == AF_INET6) |
| udphoff = sizeof(struct ipv6hdr); |
| else |
| #endif |
| udphoff = ip_hdrlen(skb); |
| |
| uh = skb_header_pointer(skb, udphoff, sizeof(_udph), &_udph); |
| if (uh == NULL) |
| return 0; |
| |
| if (uh->check != 0) { |
| switch (skb->ip_summed) { |
| case CHECKSUM_NONE: |
| skb->csum = skb_checksum(skb, udphoff, |
| skb->len - udphoff, 0); |
| /* fall through */ |
| case CHECKSUM_COMPLETE: |
| #ifdef CONFIG_IP_VS_IPV6 |
| if (af == AF_INET6) { |
| if (csum_ipv6_magic(&ipv6_hdr(skb)->saddr, |
| &ipv6_hdr(skb)->daddr, |
| skb->len - udphoff, |
| ipv6_hdr(skb)->nexthdr, |
| skb->csum)) { |
| IP_VS_DBG_RL_PKT(0, af, pp, skb, 0, |
| "Failed checksum for"); |
| return 0; |
| } |
| } else |
| #endif |
| if (csum_tcpudp_magic(ip_hdr(skb)->saddr, |
| ip_hdr(skb)->daddr, |
| skb->len - udphoff, |
| ip_hdr(skb)->protocol, |
| skb->csum)) { |
| IP_VS_DBG_RL_PKT(0, af, pp, skb, 0, |
| "Failed checksum for"); |
| return 0; |
| } |
| break; |
| default: |
| /* No need to checksum. */ |
| break; |
| } |
| } |
| return 1; |
| } |
| |
| static inline __u16 udp_app_hashkey(__be16 port) |
| { |
| return (((__force u16)port >> UDP_APP_TAB_BITS) ^ (__force u16)port) |
| & UDP_APP_TAB_MASK; |
| } |
| |
| |
| static int udp_register_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc) |
| { |
| struct ip_vs_app *i; |
| __u16 hash; |
| __be16 port = inc->port; |
| int ret = 0; |
| struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_UDP); |
| |
| hash = udp_app_hashkey(port); |
| |
| list_for_each_entry(i, &ipvs->udp_apps[hash], p_list) { |
| if (i->port == port) { |
| ret = -EEXIST; |
| goto out; |
| } |
| } |
| list_add_rcu(&inc->p_list, &ipvs->udp_apps[hash]); |
| atomic_inc(&pd->appcnt); |
| |
| out: |
| return ret; |
| } |
| |
| |
| static void |
| udp_unregister_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc) |
| { |
| struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_UDP); |
| |
| atomic_dec(&pd->appcnt); |
| list_del_rcu(&inc->p_list); |
| } |
| |
| |
| static int udp_app_conn_bind(struct ip_vs_conn *cp) |
| { |
| struct netns_ipvs *ipvs = cp->ipvs; |
| int hash; |
| struct ip_vs_app *inc; |
| int result = 0; |
| |
| /* Default binding: bind app only for NAT */ |
| if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) |
| return 0; |
| |
| /* Lookup application incarnations and bind the right one */ |
| hash = udp_app_hashkey(cp->vport); |
| |
| list_for_each_entry_rcu(inc, &ipvs->udp_apps[hash], p_list) { |
| if (inc->port == cp->vport) { |
| if (unlikely(!ip_vs_app_inc_get(inc))) |
| break; |
| |
| IP_VS_DBG_BUF(9, "%s(): Binding conn %s:%u->" |
| "%s:%u to app %s on port %u\n", |
| __func__, |
| IP_VS_DBG_ADDR(cp->af, &cp->caddr), |
| ntohs(cp->cport), |
| IP_VS_DBG_ADDR(cp->af, &cp->vaddr), |
| ntohs(cp->vport), |
| inc->name, ntohs(inc->port)); |
| |
| cp->app = inc; |
| if (inc->init_conn) |
| result = inc->init_conn(inc, cp); |
| break; |
| } |
| } |
| |
| return result; |
| } |
| |
| |
| static const int udp_timeouts[IP_VS_UDP_S_LAST+1] = { |
| [IP_VS_UDP_S_NORMAL] = 5*60*HZ, |
| [IP_VS_UDP_S_LAST] = 2*HZ, |
| }; |
| |
| static const char *const udp_state_name_table[IP_VS_UDP_S_LAST+1] = { |
| [IP_VS_UDP_S_NORMAL] = "UDP", |
| [IP_VS_UDP_S_LAST] = "BUG!", |
| }; |
| |
| static const char * udp_state_name(int state) |
| { |
| if (state >= IP_VS_UDP_S_LAST) |
| return "ERR!"; |
| return udp_state_name_table[state] ? udp_state_name_table[state] : "?"; |
| } |
| |
| static void |
| udp_state_transition(struct ip_vs_conn *cp, int direction, |
| const struct sk_buff *skb, |
| struct ip_vs_proto_data *pd) |
| { |
| if (unlikely(!pd)) { |
| pr_err("UDP no ns data\n"); |
| return; |
| } |
| |
| cp->timeout = pd->timeout_table[IP_VS_UDP_S_NORMAL]; |
| if (direction == IP_VS_DIR_OUTPUT) |
| ip_vs_control_assure_ct(cp); |
| } |
| |
| static int __udp_init(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd) |
| { |
| ip_vs_init_hash_table(ipvs->udp_apps, UDP_APP_TAB_SIZE); |
| pd->timeout_table = ip_vs_create_timeout_table((int *)udp_timeouts, |
| sizeof(udp_timeouts)); |
| if (!pd->timeout_table) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| static void __udp_exit(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd) |
| { |
| kfree(pd->timeout_table); |
| } |
| |
| |
| struct ip_vs_protocol ip_vs_protocol_udp = { |
| .name = "UDP", |
| .protocol = IPPROTO_UDP, |
| .num_states = IP_VS_UDP_S_LAST, |
| .dont_defrag = 0, |
| .init = NULL, |
| .exit = NULL, |
| .init_netns = __udp_init, |
| .exit_netns = __udp_exit, |
| .conn_schedule = udp_conn_schedule, |
| .conn_in_get = ip_vs_conn_in_get_proto, |
| .conn_out_get = ip_vs_conn_out_get_proto, |
| .snat_handler = udp_snat_handler, |
| .dnat_handler = udp_dnat_handler, |
| .csum_check = udp_csum_check, |
| .state_transition = udp_state_transition, |
| .state_name = udp_state_name, |
| .register_app = udp_register_app, |
| .unregister_app = udp_unregister_app, |
| .app_conn_bind = udp_app_conn_bind, |
| .debug_packet = ip_vs_tcpudp_debug_packet, |
| .timeout_change = NULL, |
| }; |