From 8052ba292559f907ea2ad4c827d83c195046dfe1 Mon Sep 17 00:00:00 2001 From: Alex Gartrell Date: Tue, 9 Sep 2014 16:40:28 -0700 Subject: [PATCH] ipvs: support ipv4 in ipv6 and ipv6 in ipv4 tunnel forwarding Pull the common logic for preparing an skb to prepend the header into a single function and then set fields such that they can be used in either case (generalize tos and tclass to dscp, hop_limit and ttl to ttl, etc) Signed-off-by: Alex Gartrell Acked-by: Julian Anastasov Signed-off-by: Simon Horman --- net/netfilter/ipvs/ip_vs_conn.c | 12 ++- net/netfilter/ipvs/ip_vs_xmit.c | 148 +++++++++++++++++++++++--------- 2 files changed, 117 insertions(+), 43 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c index fdb4880a3a79..13e9cee02c81 100644 --- a/net/netfilter/ipvs/ip_vs_conn.c +++ b/net/netfilter/ipvs/ip_vs_conn.c @@ -488,7 +488,12 @@ static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp) break; case IP_VS_CONN_F_TUNNEL: - cp->packet_xmit = ip_vs_tunnel_xmit; +#ifdef CONFIG_IP_VS_IPV6 + if (cp->daf == AF_INET6) + cp->packet_xmit = ip_vs_tunnel_xmit_v6; + else +#endif + cp->packet_xmit = ip_vs_tunnel_xmit; break; case IP_VS_CONN_F_DROUTE: @@ -514,7 +519,10 @@ static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp) break; case IP_VS_CONN_F_TUNNEL: - cp->packet_xmit = ip_vs_tunnel_xmit_v6; + if (cp->daf == AF_INET6) + cp->packet_xmit = ip_vs_tunnel_xmit_v6; + else + cp->packet_xmit = ip_vs_tunnel_xmit; break; case IP_VS_CONN_F_DROUTE: diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c index fa2fdd7421b7..91f17c1eb8a2 100644 --- a/net/netfilter/ipvs/ip_vs_xmit.c +++ b/net/netfilter/ipvs/ip_vs_xmit.c @@ -824,6 +824,81 @@ tx_error: } #endif +/* When forwarding a packet, we must ensure that we've got enough headroom + * for the encapsulation packet in the skb. This also gives us an + * opportunity to figure out what the payload_len, dsfield, ttl, and df + * values should be, so that we won't need to look at the old ip header + * again + */ +static struct sk_buff * +ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af, + unsigned int max_headroom, __u8 *next_protocol, + __u32 *payload_len, __u8 *dsfield, __u8 *ttl, + __be16 *df) +{ + struct sk_buff *new_skb = NULL; + struct iphdr *old_iph = NULL; +#ifdef CONFIG_IP_VS_IPV6 + struct ipv6hdr *old_ipv6h = NULL; +#endif + + if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) { + new_skb = skb_realloc_headroom(skb, max_headroom); + if (!new_skb) + goto error; + consume_skb(skb); + skb = new_skb; + } + +#ifdef CONFIG_IP_VS_IPV6 + if (skb_af == AF_INET6) { + old_ipv6h = ipv6_hdr(skb); + *next_protocol = IPPROTO_IPV6; + if (payload_len) + *payload_len = + ntohs(old_ipv6h->payload_len) + + sizeof(*old_ipv6h); + *dsfield = ipv6_get_dsfield(old_ipv6h); + *ttl = old_ipv6h->hop_limit; + if (df) + *df = 0; + } else +#endif + { + old_iph = ip_hdr(skb); + /* Copy DF, reset fragment offset and MF */ + if (df) + *df = (old_iph->frag_off & htons(IP_DF)); + *next_protocol = IPPROTO_IPIP; + + /* fix old IP header checksum */ + ip_send_check(old_iph); + *dsfield = ipv4_get_dsfield(old_iph); + *ttl = old_iph->ttl; + if (payload_len) + *payload_len = ntohs(old_iph->tot_len); + } + + return skb; +error: + kfree_skb(skb); + return ERR_PTR(-ENOMEM); +} + +static inline int __tun_gso_type_mask(int encaps_af, int orig_af) +{ + if (encaps_af == AF_INET) { + if (orig_af == AF_INET) + return SKB_GSO_IPIP; + + return SKB_GSO_SIT; + } + + /* GSO: we need to provide proper SKB_GSO_ value for IPv6: + * SKB_GSO_SIT/IPV6 + */ + return 0; +} /* * IP Tunneling transmitter @@ -852,9 +927,11 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, struct rtable *rt; /* Route to the other host */ __be32 saddr; /* Source for tunnel */ struct net_device *tdev; /* Device to other host */ - struct iphdr *old_iph = ip_hdr(skb); - u8 tos = old_iph->tos; - __be16 df; + __u8 next_protocol = 0; + __u8 dsfield = 0; + __u8 ttl = 0; + __be16 df = 0; + __be16 *dfp = NULL; struct iphdr *iph; /* Our new IP header */ unsigned int max_headroom; /* The extra header space needed */ int ret, local; @@ -877,29 +954,21 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, rt = skb_rtable(skb); tdev = rt->dst.dev; - /* Copy DF, reset fragment offset and MF */ - df = sysctl_pmtu_disc(ipvs) ? old_iph->frag_off & htons(IP_DF) : 0; - /* * Okay, now see if we can stuff it in the buffer as-is. */ max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr); - if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) { - struct sk_buff *new_skb = - skb_realloc_headroom(skb, max_headroom); - - if (!new_skb) - goto tx_error; - consume_skb(skb); - skb = new_skb; - old_iph = ip_hdr(skb); - } - - /* fix old IP header checksum */ - ip_send_check(old_iph); + /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */ + dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL; + skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom, + &next_protocol, NULL, &dsfield, + &ttl, dfp); + if (IS_ERR(skb)) + goto tx_error; - skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP); + skb = iptunnel_handle_offloads( + skb, false, __tun_gso_type_mask(AF_INET, cp->af)); if (IS_ERR(skb)) goto tx_error; @@ -916,11 +985,11 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp, iph->version = 4; iph->ihl = sizeof(struct iphdr)>>2; iph->frag_off = df; - iph->protocol = IPPROTO_IPIP; - iph->tos = tos; + iph->protocol = next_protocol; + iph->tos = dsfield; iph->daddr = cp->daddr.ip; iph->saddr = saddr; - iph->ttl = old_iph->ttl; + iph->ttl = ttl; ip_select_ident(skb, NULL); /* Another hack: avoid icmp_send in ip_fragment */ @@ -953,7 +1022,10 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp, struct rt6_info *rt; /* Route to the other host */ struct in6_addr saddr; /* Source for tunnel */ struct net_device *tdev; /* Device to other host */ - struct ipv6hdr *old_iph = ipv6_hdr(skb); + __u8 next_protocol = 0; + __u32 payload_len = 0; + __u8 dsfield = 0; + __u8 ttl = 0; struct ipv6hdr *iph; /* Our new IP header */ unsigned int max_headroom; /* The extra header space needed */ int ret, local; @@ -981,19 +1053,14 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp, */ max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr); - if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) { - struct sk_buff *new_skb = - skb_realloc_headroom(skb, max_headroom); - - if (!new_skb) - goto tx_error; - consume_skb(skb); - skb = new_skb; - old_iph = ipv6_hdr(skb); - } + skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom, + &next_protocol, &payload_len, + &dsfield, &ttl, NULL); + if (IS_ERR(skb)) + goto tx_error; - /* GSO: we need to provide proper SKB_GSO_ value for IPv6 */ - skb = iptunnel_handle_offloads(skb, false, 0); /* SKB_GSO_SIT/IPV6 */ + skb = iptunnel_handle_offloads( + skb, false, __tun_gso_type_mask(AF_INET6, cp->af)); if (IS_ERR(skb)) goto tx_error; @@ -1008,14 +1075,13 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp, */ iph = ipv6_hdr(skb); iph->version = 6; - iph->nexthdr = IPPROTO_IPV6; - iph->payload_len = old_iph->payload_len; - be16_add_cpu(&iph->payload_len, sizeof(*old_iph)); + iph->nexthdr = next_protocol; + iph->payload_len = htons(payload_len); memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl)); - ipv6_change_dsfield(iph, 0, ipv6_get_dsfield(old_iph)); + ipv6_change_dsfield(iph, 0, dsfield); iph->daddr = cp->daddr.in6; iph->saddr = saddr; - iph->hop_limit = old_iph->hop_limit; + iph->hop_limit = ttl; /* Another hack: avoid icmp_send in ip_fragment */ skb->ignore_df = 1; -- 2.39.2