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Message-Id: <1411994363-8451-23-git-send-email-pablo@netfilter.org>
Date: Mon, 29 Sep 2014 14:39:11 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 22/34] ipvs: support ipv4 in ipv6 and ipv6 in ipv4 tunnel forwarding
From: Alex Gartrell <agartrell@...com>
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 <agartrell@...com>
Acked-by: Julian Anastasov <ja@....bg>
Signed-off-by: Simon Horman <horms@...ge.net.au>
---
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 fdb4880..13e9cee 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 fa2fdd7..91f17c1 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;
--
1.7.10.4
--
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