From 067b207b281db5e3f03f8d244286c20f61aa2343 Mon Sep 17 00:00:00 2001 From: James Chapman Date: Thu, 5 Jul 2007 17:08:05 -0700 Subject: [UDP]: Cleanup UDP encapsulation code This cleanup fell out after adding L2TP support where a new encap_rcv funcptr was added to struct udp_sock. Have XFRM use the new encap_rcv funcptr, which allows us to move the XFRM encap code from udp.c into xfrm4_input.c. Make xfrm4_rcv_encap() static since it is no longer called externally. Signed-off-by: James Chapman Acked-by: Patrick McHardy Signed-off-by: David S. Miller --- net/ipv4/xfrm4_input.c | 114 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 106 insertions(+), 8 deletions(-) (limited to 'net/ipv4/xfrm4_input.c') diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c index fa1902dc81b8..2fa108245413 100644 --- a/net/ipv4/xfrm4_input.c +++ b/net/ipv4/xfrm4_input.c @@ -16,13 +16,6 @@ #include #include -int xfrm4_rcv(struct sk_buff *skb) -{ - return xfrm4_rcv_encap(skb, 0); -} - -EXPORT_SYMBOL(xfrm4_rcv); - static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq) { switch (nexthdr) { @@ -53,7 +46,7 @@ drop: } #endif -int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) +static int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) { __be32 spi, seq; struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH]; @@ -167,3 +160,108 @@ drop: kfree_skb(skb); return 0; } + +/* If it's a keepalive packet, then just eat it. + * If it's an encapsulated packet, then pass it to the + * IPsec xfrm input. + * Returns 0 if skb passed to xfrm or was dropped. + * Returns >0 if skb should be passed to UDP. + * Returns <0 if skb should be resubmitted (-ret is protocol) + */ +int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) +{ + struct udp_sock *up = udp_sk(sk); + struct udphdr *uh; + struct iphdr *iph; + int iphlen, len; + int ret; + + __u8 *udpdata; + __be32 *udpdata32; + __u16 encap_type = up->encap_type; + + /* if this is not encapsulated socket, then just return now */ + if (!encap_type) + return 1; + + /* If this is a paged skb, make sure we pull up + * whatever data we need to look at. */ + len = skb->len - sizeof(struct udphdr); + if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) + return 1; + + /* Now we can get the pointers */ + uh = udp_hdr(skb); + udpdata = (__u8 *)uh + sizeof(struct udphdr); + udpdata32 = (__be32 *)udpdata; + + switch (encap_type) { + default: + case UDP_ENCAP_ESPINUDP: + /* Check if this is a keepalive packet. If so, eat it. */ + if (len == 1 && udpdata[0] == 0xff) { + goto drop; + } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { + /* ESP Packet without Non-ESP header */ + len = sizeof(struct udphdr); + } else + /* Must be an IKE packet.. pass it through */ + return 1; + break; + case UDP_ENCAP_ESPINUDP_NON_IKE: + /* Check if this is a keepalive packet. If so, eat it. */ + if (len == 1 && udpdata[0] == 0xff) { + goto drop; + } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && + udpdata32[0] == 0 && udpdata32[1] == 0) { + + /* ESP Packet with Non-IKE marker */ + len = sizeof(struct udphdr) + 2 * sizeof(u32); + } else + /* Must be an IKE packet.. pass it through */ + return 1; + break; + } + + /* At this point we are sure that this is an ESPinUDP packet, + * so we need to remove 'len' bytes from the packet (the UDP + * header and optional ESP marker bytes) and then modify the + * protocol to ESP, and then call into the transform receiver. + */ + if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) + goto drop; + + /* Now we can update and verify the packet length... */ + iph = ip_hdr(skb); + iphlen = iph->ihl << 2; + iph->tot_len = htons(ntohs(iph->tot_len) - len); + if (skb->len < iphlen + len) { + /* packet is too small!?! */ + goto drop; + } + + /* pull the data buffer up to the ESP header and set the + * transport header to point to ESP. Keep UDP on the stack + * for later. + */ + __skb_pull(skb, len); + skb_reset_transport_header(skb); + + /* modify the protocol (it's ESP!) */ + iph->protocol = IPPROTO_ESP; + + /* process ESP */ + ret = xfrm4_rcv_encap(skb, encap_type); + return ret; + +drop: + kfree_skb(skb); + return 0; +} + +int xfrm4_rcv(struct sk_buff *skb) +{ + return xfrm4_rcv_encap(skb, 0); +} + +EXPORT_SYMBOL(xfrm4_rcv); -- cgit v1.2.3-59-g8ed1b