/* * 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.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, ip_hdr(skb)->protocol, ip_hdr(skb)->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 *skb, struct ip_vs_protocol *pp, struct ip_vs_conn *cp) { struct udphdr *udph; const unsigned int udphoff = ip_hdrlen(skb); /* csum_check requires unshared skb */ if (!skb_make_writable(skb, udphoff+sizeof(*udph))) return 0; if (unlikely(cp->app != NULL)) { /* Some checks before mangling */ if (pp->csum_check && !pp->csum_check(skb, pp)) return 0; /* * Call application helper if needed */ if (!ip_vs_app_pkt_out(cp, skb)) return 0; } udph = (void *)ip_hdr(skb) + 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 (skb->ip_summed == CHECKSUM_COMPLETE) skb->ip_summed = CHECKSUM_NONE; } else { /* full checksum calculation */ udph->check = 0; skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0); udph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr, skb->len - udphoff, cp->protocol, skb->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 *skb, struct ip_vs_protocol *pp, struct ip_vs_conn *cp) { struct udphdr *udph; unsigned int udphoff = ip_hdrlen(skb); /* csum_check requires unshared skb */ if (!skb_make_writable(skb, udphoff+sizeof(*udph))) return 0; if (unlikely(cp->app != NULL)) { /* Some checks before mangling */ if (pp->csum_check && !pp->csum_check(skb, pp)) return 0; /* * Attempt ip_vs_app call. * It will fix ip_vs_conn */ if (!ip_vs_app_pkt_in(cp, skb)) return 0; } udph = (void *)ip_hdr(skb) + 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 (skb->ip_summed == CHECKSUM_COMPLETE) skb->ip_summed = CHECKSUM_NONE; } else { /* full checksum calculation */ udph->check = 0; skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0); udph->check = csum_tcpudp_magic(cp->caddr, cp->daddr, 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(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(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, skb->len - udphoff, ip_hdr(skb)->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", __func__, 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, .num_states = IP_VS_UDP_S_LAST, .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, };