From 4856c84c1358b79852743ac64e50c1e9d5118f05 Mon Sep 17 00:00:00 2001 From: Malcolm Turnbull Date: Fri, 5 Sep 2008 11:17:13 +1000 Subject: [PATCH] ipvs: load balance IPv4 connections from a local process MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This allows IPVS to load balance connections made by a local process. For example a proxy server running locally. External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer Signed-off-by: Siim Põder Signed-off-by: Malcolm Turnbull Signed-off-by: Simon Horman --- net/ipv4/ipvs/ip_vs_core.c | 224 +++++++++++++++++++------------- net/ipv4/ipvs/ip_vs_proto_tcp.c | 4 +- 2 files changed, 134 insertions(+), 94 deletions(-) diff --git a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c index 7d3de9db5ac5..26e3d99bbeea 100644 --- a/net/ipv4/ipvs/ip_vs_core.c +++ b/net/ipv4/ipvs/ip_vs_core.c @@ -651,12 +651,53 @@ void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct ip_vs_protocol *pp, } #endif +/* Handle relevant response ICMP messages - forward to the right + * destination host. Used for NAT and local client. + */ +static int handle_response_icmp(struct sk_buff *skb, struct iphdr *iph, + struct iphdr *cih, struct ip_vs_conn *cp, + struct ip_vs_protocol *pp, + unsigned int offset, unsigned int ihl) +{ + unsigned int verdict = NF_DROP; + + if (IP_VS_FWD_METHOD(cp) != 0) { + IP_VS_ERR("shouldn't reach here, because the box is on the " + "half connection in the tun/dr module.\n"); + } + + /* Ensure the checksum is correct */ + if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) { + /* Failed checksum! */ + IP_VS_DBG(1, + "Forward ICMP: failed checksum from %d.%d.%d.%d!\n", + NIPQUAD(iph->saddr)); + goto out; + } + + if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol) + offset += 2 * sizeof(__u16); + if (!skb_make_writable(skb, offset)) + goto out; + + ip_vs_nat_icmp(skb, pp, cp, 1); + + /* do the statistics and put it back */ + ip_vs_out_stats(cp, skb); + + skb->ipvs_property = 1; + verdict = NF_ACCEPT; + +out: + __ip_vs_conn_put(cp); + + return verdict; +} + /* * Handle ICMP messages in the inside-to-outside direction (outgoing). - * Find any that might be relevant, check against existing connections, - * forward to the right destination host if relevant. + * Find any that might be relevant, check against existing connections. * Currently handles error types - unreachable, quench, ttl exceeded. - * (Only used in VS/NAT) */ static int ip_vs_out_icmp(struct sk_buff *skb, int *related) { @@ -666,7 +707,7 @@ static int ip_vs_out_icmp(struct sk_buff *skb, int *related) struct ip_vs_iphdr ciph; struct ip_vs_conn *cp; struct ip_vs_protocol *pp; - unsigned int offset, ihl, verdict; + unsigned int offset, ihl; *related = 1; @@ -725,38 +766,7 @@ static int ip_vs_out_icmp(struct sk_buff *skb, int *related) if (!cp) return NF_ACCEPT; - verdict = NF_DROP; - - if (IP_VS_FWD_METHOD(cp) != 0) { - IP_VS_ERR("shouldn't reach here, because the box is on the " - "half connection in the tun/dr module.\n"); - } - - /* Ensure the checksum is correct */ - if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) { - /* Failed checksum! */ - IP_VS_DBG(1, "Forward ICMP: failed checksum from %d.%d.%d.%d!\n", - NIPQUAD(iph->saddr)); - goto out; - } - - if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol) - offset += 2 * sizeof(__u16); - if (!skb_make_writable(skb, offset)) - goto out; - - ip_vs_nat_icmp(skb, pp, cp, 1); - - /* do the statistics and put it back */ - ip_vs_out_stats(cp, skb); - - skb->ipvs_property = 1; - verdict = NF_ACCEPT; - - out: - __ip_vs_conn_put(cp); - - return verdict; + return handle_response_icmp(skb, iph, cih, cp, pp, offset, ihl); } #ifdef CONFIG_IP_VS_IPV6 @@ -875,10 +885,76 @@ static inline int is_tcp_reset(const struct sk_buff *skb, int nh_len) return th->rst; } +/* Handle response packets: rewrite addresses and send away... + * Used for NAT and local client. + */ +static unsigned int +handle_response(int af, struct sk_buff *skb, struct ip_vs_protocol *pp, + struct ip_vs_conn *cp, int ihl) +{ + IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet"); + + if (!skb_make_writable(skb, ihl)) + goto drop; + + /* mangle the packet */ + if (pp->snat_handler && !pp->snat_handler(skb, pp, cp)) + goto drop; + +#ifdef CONFIG_IP_VS_IPV6 + if (af == AF_INET6) + ipv6_hdr(skb)->saddr = cp->vaddr.in6; + else +#endif + { + ip_hdr(skb)->saddr = cp->vaddr.ip; + ip_send_check(ip_hdr(skb)); + } + + /* For policy routing, packets originating from this + * machine itself may be routed differently to packets + * passing through. We want this packet to be routed as + * if it came from this machine itself. So re-compute + * the routing information. + */ +#ifdef CONFIG_IP_VS_IPV6 + if (af == AF_INET6) { + if (ip6_route_me_harder(skb) != 0) + goto drop; + } else +#endif + if (ip_route_me_harder(skb, RTN_LOCAL) != 0) + goto drop; + + /* For policy routing, packets originating from this + * machine itself may be routed differently to packets + * passing through. We want this packet to be routed as + * if it came from this machine itself. So re-compute + * the routing information. + */ + if (ip_route_me_harder(skb, RTN_LOCAL) != 0) + goto drop; + + IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT"); + + ip_vs_out_stats(cp, skb); + ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp); + ip_vs_conn_put(cp); + + skb->ipvs_property = 1; + + LeaveFunction(11); + return NF_ACCEPT; + +drop: + ip_vs_conn_put(cp); + kfree_skb(skb); + return NF_STOLEN; +} + /* * It is hooked at the NF_INET_FORWARD chain, used only for VS/NAT. - * Check if outgoing packet belongs to the established ip_vs_conn, - * rewrite addresses of the packet and send it on its way... + * Check if outgoing packet belongs to the established ip_vs_conn. */ static unsigned int ip_vs_out(unsigned int hooknum, struct sk_buff *skb, @@ -987,55 +1063,7 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, return NF_ACCEPT; } - IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet"); - - if (!skb_make_writable(skb, iph.len)) - goto drop; - - /* mangle the packet */ - if (pp->snat_handler && !pp->snat_handler(skb, pp, cp)) - goto drop; - -#ifdef CONFIG_IP_VS_IPV6 - if (af == AF_INET6) - ipv6_hdr(skb)->saddr = cp->vaddr.in6; - else -#endif - { - ip_hdr(skb)->saddr = cp->vaddr.ip; - ip_send_check(ip_hdr(skb)); - } - - /* For policy routing, packets originating from this - * machine itself may be routed differently to packets - * passing through. We want this packet to be routed as - * if it came from this machine itself. So re-compute - * the routing information. - */ -#ifdef CONFIG_IP_VS_IPV6 - if (af == AF_INET6) { - if (ip6_route_me_harder(skb) != 0) - goto drop; - } else -#endif - if (ip_route_me_harder(skb, RTN_LOCAL) != 0) - goto drop; - - IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT"); - - ip_vs_out_stats(cp, skb); - ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp); - ip_vs_conn_put(cp); - - skb->ipvs_property = 1; - - LeaveFunction(11); - return NF_ACCEPT; - - drop: - ip_vs_conn_put(cp); - kfree_skb(skb); - return NF_STOLEN; + return handle_response(af, skb, pp, cp, iph.len); } @@ -1111,8 +1139,14 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum) ip_vs_fill_iphdr(AF_INET, cih, &ciph); /* The embedded headers contain source and dest in reverse order */ cp = pp->conn_in_get(AF_INET, skb, pp, &ciph, offset, 1); - if (!cp) + if (!cp) { + /* The packet could also belong to a local client */ + cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1); + if (cp) + return handle_response_icmp(skb, iph, cih, cp, pp, + offset, ihl); return NF_ACCEPT; + } verdict = NF_DROP; @@ -1244,11 +1278,12 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, ip_vs_fill_iphdr(af, skb_network_header(skb), &iph); /* - * Big tappo: only PACKET_HOST (neither loopback nor mcasts) - * ... don't know why 1st test DOES NOT include 2nd (?) + * Big tappo: only PACKET_HOST, including loopback for local client + * Don't handle local packets on IPv6 for now */ - if (unlikely(skb->pkt_type != PACKET_HOST - || skb->dev->flags & IFF_LOOPBACK || skb->sk)) { + if (unlikely(skb->pkt_type != PACKET_HOST || + (af == AF_INET6 || (skb->dev->flags & IFF_LOOPBACK || + skb->sk)))) { IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s ignored\n", skb->pkt_type, iph.protocol, @@ -1277,6 +1312,11 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, if (unlikely(!cp)) { int v; + /* For local client packets, it could be a response */ + cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0); + if (cp) + return handle_response(af, skb, pp, cp, iph.len); + if (!pp->conn_schedule(af, skb, pp, &v, &cp)) return v; } diff --git a/net/ipv4/ipvs/ip_vs_proto_tcp.c b/net/ipv4/ipvs/ip_vs_proto_tcp.c index de8ed73997c7..808e8be0280a 100644 --- a/net/ipv4/ipvs/ip_vs_proto_tcp.c +++ b/net/ipv4/ipvs/ip_vs_proto_tcp.c @@ -166,7 +166,7 @@ tcp_snat_handler(struct sk_buff *skb, tcph->source = cp->vport; /* Adjust TCP checksums */ - if (!cp->app) { + if (!cp->app && (tcph->check != 0)) { /* Only port and addr are changed, do fast csum update */ tcp_fast_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr, cp->dport, cp->vport); @@ -235,7 +235,7 @@ tcp_dnat_handler(struct sk_buff *skb, /* * Adjust TCP checksums */ - if (!cp->app) { + if (!cp->app && (tcph->check != 0)) { /* Only port and addr are changed, do fast csum update */ tcp_fast_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr, cp->vport, cp->dport);