diff options
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_proto_udp.c')
-rw-r--r-- | net/netfilter/ipvs/ip_vs_proto_udp.c | 533 |
1 files changed, 533 insertions, 0 deletions
diff --git a/net/netfilter/ipvs/ip_vs_proto_udp.c b/net/netfilter/ipvs/ip_vs_proto_udp.c new file mode 100644 index 00000000000..6eb6039d634 --- /dev/null +++ b/net/netfilter/ipvs/ip_vs_proto_udp.c @@ -0,0 +1,533 @@ +/* + * 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: + * + */ + +#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 struct ip_vs_conn * +udp_conn_in_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp, + const struct ip_vs_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(af, iph->protocol, + &iph->saddr, pptr[0], + &iph->daddr, pptr[1]); + } else { + cp = ip_vs_conn_in_get(af, iph->protocol, + &iph->daddr, pptr[1], + &iph->saddr, pptr[0]); + } + + return cp; +} + + +static struct ip_vs_conn * +udp_conn_out_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp, + const struct ip_vs_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_out_get(af, iph->protocol, + &iph->saddr, pptr[0], + &iph->daddr, pptr[1]); + } else { + cp = ip_vs_conn_out_get(af, iph->protocol, + &iph->daddr, pptr[1], + &iph->saddr, pptr[0]); + } + + return cp; +} + + +static int +udp_conn_schedule(int af, 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; + struct ip_vs_iphdr iph; + + ip_vs_fill_iphdr(af, skb_network_header(skb), &iph); + + uh = skb_header_pointer(skb, iph.len, sizeof(_udph), &_udph); + if (uh == NULL) { + *verdict = NF_DROP; + return 0; + } + + svc = ip_vs_service_get(af, skb->mark, iph.protocol, + &iph.daddr, uh->dest); + if (svc) { + 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(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 udphdr *udph; + unsigned int udphoff; + int oldlen; + +#ifdef CONFIG_IP_VS_IPV6 + if (cp->af == AF_INET6) + udphoff = sizeof(struct ipv6hdr); + else +#endif + udphoff = ip_hdrlen(skb); + oldlen = skb->len - udphoff; + + /* 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(cp->af, skb, pp)) + return 0; + + /* + * Call application helper if needed + */ + if (!ip_vs_app_pkt_out(cp, skb)) + return 0; + } + + 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, + htonl(oldlen), + htonl(skb->len - udphoff)); + } else if (!cp->app && (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 = 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; + 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; + int oldlen; + +#ifdef CONFIG_IP_VS_IPV6 + if (cp->af == AF_INET6) + udphoff = sizeof(struct ipv6hdr); + else +#endif + udphoff = ip_hdrlen(skb); + oldlen = skb->len - udphoff; + + /* 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(cp->af, 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 *)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->daddr, &cp->vaddr, + htonl(oldlen), + htonl(skb->len - udphoff)); + } else if (!cp->app && (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 = 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); + 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, 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, 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_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); + 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, +}; |