| /* |
| * ip_vs_proto_udp.c: UDP load balancing support for IPVS |
| * |
| * Version: $Id: ip_vs_proto_udp.c,v 1.3 2002/11/30 01:50:35 wensong Exp $ |
| * |
| * 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: |
| * |
| */ |
| |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #include <linux/kernel.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/udp.h> |
| |
| #include <net/ip_vs.h> |
| #include <net/ip.h> |
| |
| static struct ip_vs_conn * |
| udp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp, |
| const struct iphdr *iph, unsigned int proto_off, int inverse) |
| { |
| struct ip_vs_conn *cp; |
| __be16 _ports[2], *pptr; |
| |
| pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports); |
| if (pptr == NULL) |
| return NULL; |
| |
| if (likely(!inverse)) { |
| cp = ip_vs_conn_in_get(iph->protocol, |
| iph->saddr, pptr[0], |
| iph->daddr, pptr[1]); |
| } else { |
| cp = ip_vs_conn_in_get(iph->protocol, |
| iph->daddr, pptr[1], |
| iph->saddr, pptr[0]); |
| } |
| |
| return cp; |
| } |
| |
| |
| static struct ip_vs_conn * |
| udp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp, |
| const struct iphdr *iph, unsigned int proto_off, int inverse) |
| { |
| struct ip_vs_conn *cp; |
| __be16 _ports[2], *pptr; |
| |
| pptr = skb_header_pointer(skb, ip_hdrlen(skb), |
| sizeof(_ports), _ports); |
| if (pptr == NULL) |
| return NULL; |
| |
| if (likely(!inverse)) { |
| cp = ip_vs_conn_out_get(iph->protocol, |
| iph->saddr, pptr[0], |
| iph->daddr, pptr[1]); |
| } else { |
| cp = ip_vs_conn_out_get(iph->protocol, |
| iph->daddr, pptr[1], |
| iph->saddr, pptr[0]); |
| } |
| |
| return cp; |
| } |
| |
| |
| static int |
| udp_conn_schedule(struct sk_buff *skb, struct ip_vs_protocol *pp, |
| int *verdict, struct ip_vs_conn **cpp) |
| { |
| struct ip_vs_service *svc; |
| struct udphdr _udph, *uh; |
| |
| uh = skb_header_pointer(skb, ip_hdrlen(skb), |
| sizeof(_udph), &_udph); |
| if (uh == NULL) { |
| *verdict = NF_DROP; |
| return 0; |
| } |
| |
| if ((svc = ip_vs_service_get(skb->mark, skb->nh.iph->protocol, |
| skb->nh.iph->daddr, uh->dest))) { |
| if (ip_vs_todrop()) { |
| /* |
| * It seems that we are very loaded. |
| * We have to drop this packet :( |
| */ |
| ip_vs_service_put(svc); |
| *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); |
| if (!*cpp) { |
| *verdict = ip_vs_leave(svc, skb, pp); |
| return 0; |
| } |
| ip_vs_service_put(svc); |
| } |
| return 1; |
| } |
| |
| |
| static inline void |
| udp_fast_csum_update(struct udphdr *uhdr, __be32 oldip, __be32 newip, |
| __be16 oldport, __be16 newport) |
| { |
| uhdr->check = |
| csum_fold(ip_vs_check_diff4(oldip, newip, |
| ip_vs_check_diff2(oldport, newport, |
| ~csum_unfold(uhdr->check)))); |
| if (!uhdr->check) |
| uhdr->check = CSUM_MANGLED_0; |
| } |
| |
| static int |
| udp_snat_handler(struct sk_buff **pskb, |
| struct ip_vs_protocol *pp, struct ip_vs_conn *cp) |
| { |
| struct udphdr *udph; |
| const unsigned int udphoff = ip_hdrlen(*pskb); |
| |
| /* csum_check requires unshared skb */ |
| if (!ip_vs_make_skb_writable(pskb, udphoff+sizeof(*udph))) |
| return 0; |
| |
| if (unlikely(cp->app != NULL)) { |
| /* Some checks before mangling */ |
| if (pp->csum_check && !pp->csum_check(*pskb, pp)) |
| return 0; |
| |
| /* |
| * Call application helper if needed |
| */ |
| if (!ip_vs_app_pkt_out(cp, pskb)) |
| return 0; |
| } |
| |
| udph = (void *)(*pskb)->nh.iph + udphoff; |
| udph->source = cp->vport; |
| |
| /* |
| * Adjust UDP checksums |
| */ |
| if (!cp->app && (udph->check != 0)) { |
| /* Only port and addr are changed, do fast csum update */ |
| udp_fast_csum_update(udph, cp->daddr, cp->vaddr, |
| cp->dport, cp->vport); |
| if ((*pskb)->ip_summed == CHECKSUM_COMPLETE) |
| (*pskb)->ip_summed = CHECKSUM_NONE; |
| } else { |
| /* full checksum calculation */ |
| udph->check = 0; |
| (*pskb)->csum = skb_checksum(*pskb, udphoff, |
| (*pskb)->len - udphoff, 0); |
| udph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr, |
| (*pskb)->len - udphoff, |
| cp->protocol, |
| (*pskb)->csum); |
| if (udph->check == 0) |
| udph->check = CSUM_MANGLED_0; |
| 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 **pskb, |
| struct ip_vs_protocol *pp, struct ip_vs_conn *cp) |
| { |
| struct udphdr *udph; |
| unsigned int udphoff = ip_hdrlen(*pskb); |
| |
| /* csum_check requires unshared skb */ |
| if (!ip_vs_make_skb_writable(pskb, udphoff+sizeof(*udph))) |
| return 0; |
| |
| if (unlikely(cp->app != NULL)) { |
| /* Some checks before mangling */ |
| if (pp->csum_check && !pp->csum_check(*pskb, pp)) |
| return 0; |
| |
| /* |
| * Attempt ip_vs_app call. |
| * It will fix ip_vs_conn |
| */ |
| if (!ip_vs_app_pkt_in(cp, pskb)) |
| return 0; |
| } |
| |
| udph = (void *)(*pskb)->nh.iph + udphoff; |
| udph->dest = cp->dport; |
| |
| /* |
| * Adjust UDP checksums |
| */ |
| if (!cp->app && (udph->check != 0)) { |
| /* Only port and addr are changed, do fast csum update */ |
| udp_fast_csum_update(udph, cp->vaddr, cp->daddr, |
| cp->vport, cp->dport); |
| if ((*pskb)->ip_summed == CHECKSUM_COMPLETE) |
| (*pskb)->ip_summed = CHECKSUM_NONE; |
| } else { |
| /* full checksum calculation */ |
| udph->check = 0; |
| (*pskb)->csum = skb_checksum(*pskb, udphoff, |
| (*pskb)->len - udphoff, 0); |
| udph->check = csum_tcpudp_magic(cp->caddr, cp->daddr, |
| (*pskb)->len - udphoff, |
| cp->protocol, |
| (*pskb)->csum); |
| if (udph->check == 0) |
| udph->check = CSUM_MANGLED_0; |
| (*pskb)->ip_summed = CHECKSUM_UNNECESSARY; |
| } |
| return 1; |
| } |
| |
| |
| static int |
| udp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp) |
| { |
| struct udphdr _udph, *uh; |
| const unsigned int 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); |
| case CHECKSUM_COMPLETE: |
| if (csum_tcpudp_magic(skb->nh.iph->saddr, |
| skb->nh.iph->daddr, |
| skb->len - udphoff, |
| skb->nh.iph->protocol, |
| skb->csum)) { |
| IP_VS_DBG_RL_PKT(0, pp, skb, 0, |
| "Failed checksum for"); |
| return 0; |
| } |
| break; |
| default: |
| /* No need to checksum. */ |
| break; |
| } |
| } |
| return 1; |
| } |
| |
| |
| /* |
| * Note: the caller guarantees that only one of register_app, |
| * unregister_app or app_conn_bind is called each time. |
| */ |
| |
| #define UDP_APP_TAB_BITS 4 |
| #define UDP_APP_TAB_SIZE (1 << UDP_APP_TAB_BITS) |
| #define UDP_APP_TAB_MASK (UDP_APP_TAB_SIZE - 1) |
| |
| static struct list_head udp_apps[UDP_APP_TAB_SIZE]; |
| static DEFINE_SPINLOCK(udp_app_lock); |
| |
| 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 ip_vs_app *inc) |
| { |
| struct ip_vs_app *i; |
| __u16 hash; |
| __be16 port = inc->port; |
| int ret = 0; |
| |
| hash = udp_app_hashkey(port); |
| |
| |
| spin_lock_bh(&udp_app_lock); |
| list_for_each_entry(i, &udp_apps[hash], p_list) { |
| if (i->port == port) { |
| ret = -EEXIST; |
| goto out; |
| } |
| } |
| list_add(&inc->p_list, &udp_apps[hash]); |
| atomic_inc(&ip_vs_protocol_udp.appcnt); |
| |
| out: |
| spin_unlock_bh(&udp_app_lock); |
| return ret; |
| } |
| |
| |
| static void |
| udp_unregister_app(struct ip_vs_app *inc) |
| { |
| spin_lock_bh(&udp_app_lock); |
| atomic_dec(&ip_vs_protocol_udp.appcnt); |
| list_del(&inc->p_list); |
| spin_unlock_bh(&udp_app_lock); |
| } |
| |
| |
| static int udp_app_conn_bind(struct ip_vs_conn *cp) |
| { |
| 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); |
| |
| spin_lock(&udp_app_lock); |
| list_for_each_entry(inc, &udp_apps[hash], p_list) { |
| if (inc->port == cp->vport) { |
| if (unlikely(!ip_vs_app_inc_get(inc))) |
| break; |
| spin_unlock(&udp_app_lock); |
| |
| IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->" |
| "%u.%u.%u.%u:%u to app %s on port %u\n", |
| __FUNCTION__, |
| NIPQUAD(cp->caddr), ntohs(cp->cport), |
| NIPQUAD(cp->vaddr), ntohs(cp->vport), |
| inc->name, ntohs(inc->port)); |
| cp->app = inc; |
| if (inc->init_conn) |
| result = inc->init_conn(inc, cp); |
| goto out; |
| } |
| } |
| spin_unlock(&udp_app_lock); |
| |
| out: |
| return result; |
| } |
| |
| |
| static 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 char * udp_state_name_table[IP_VS_UDP_S_LAST+1] = { |
| [IP_VS_UDP_S_NORMAL] = "UDP", |
| [IP_VS_UDP_S_LAST] = "BUG!", |
| }; |
| |
| |
| static int |
| udp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to) |
| { |
| return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_UDP_S_LAST, |
| udp_state_name_table, sname, to); |
| } |
| |
| 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 int |
| udp_state_transition(struct ip_vs_conn *cp, int direction, |
| const struct sk_buff *skb, |
| struct ip_vs_protocol *pp) |
| { |
| cp->timeout = pp->timeout_table[IP_VS_UDP_S_NORMAL]; |
| return 1; |
| } |
| |
| static void udp_init(struct ip_vs_protocol *pp) |
| { |
| IP_VS_INIT_HASH_TABLE(udp_apps); |
| pp->timeout_table = udp_timeouts; |
| } |
| |
| static void udp_exit(struct ip_vs_protocol *pp) |
| { |
| } |
| |
| |
| struct ip_vs_protocol ip_vs_protocol_udp = { |
| .name = "UDP", |
| .protocol = IPPROTO_UDP, |
| .dont_defrag = 0, |
| .init = udp_init, |
| .exit = udp_exit, |
| .conn_schedule = udp_conn_schedule, |
| .conn_in_get = udp_conn_in_get, |
| .conn_out_get = udp_conn_out_get, |
| .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, |
| .set_state_timeout = udp_set_state_timeout, |
| }; |