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authorVlad Yasevich <vyasevic@redhat.com>2012-11-15 08:49:18 +0000
committerDavid S. Miller <davem@davemloft.net>2012-11-15 17:36:18 -0500
commit5edbb07dc9474b7d4cd4391a2e6551ad067a0f96 (patch)
tree911a801d6101d81fb6d54dd6dde18258efb8066b /net/ipv6/udp_offload.c
parent8663e02aba154e04679c9bb1665af52021d32547 (diff)
ipv6: Separate out UDP offload functionality
Pull UDP GSO code into a separate file in preparation for moving the code out of the module. Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/udp_offload.c')
-rw-r--r--net/ipv6/udp_offload.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
new file mode 100644
index 00000000000..f964d2b366c
--- /dev/null
+++ b/net/ipv6/udp_offload.c
@@ -0,0 +1,122 @@
+/*
+ * IPV6 GSO/GRO offload support
+ * Linux INET6 implementation
+ *
+ * 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.
+ *
+ * UDPv6 GSO support
+ */
+#include <linux/skbuff.h>
+#include <net/protocol.h>
+#include <net/ipv6.h>
+#include <net/udp.h>
+#include "ip6_offload.h"
+
+static int udp6_ufo_send_check(struct sk_buff *skb)
+{
+ const struct ipv6hdr *ipv6h;
+ struct udphdr *uh;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ return -EINVAL;
+
+ ipv6h = ipv6_hdr(skb);
+ uh = udp_hdr(skb);
+
+ uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
+ IPPROTO_UDP, 0);
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ return 0;
+}
+
+static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ unsigned int mss;
+ unsigned int unfrag_ip6hlen, unfrag_len;
+ struct frag_hdr *fptr;
+ u8 *mac_start, *prevhdr;
+ u8 nexthdr;
+ u8 frag_hdr_sz = sizeof(struct frag_hdr);
+ int offset;
+ __wsum csum;
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+ goto out;
+
+ if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+ /* Packet is from an untrusted source, reset gso_segs. */
+ int type = skb_shinfo(skb)->gso_type;
+
+ if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+ !(type & (SKB_GSO_UDP))))
+ goto out;
+
+ skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
+
+ segs = NULL;
+ goto out;
+ }
+
+ /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
+ * do checksum of UDP packets sent as multiple IP fragments.
+ */
+ offset = skb_checksum_start_offset(skb);
+ csum = skb_checksum(skb, offset, skb->len - offset, 0);
+ offset += skb->csum_offset;
+ *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Check if there is enough headroom to insert fragment header. */
+ if ((skb_mac_header(skb) < skb->head + frag_hdr_sz) &&
+ pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
+ goto out;
+
+ /* Find the unfragmentable header and shift it left by frag_hdr_sz
+ * bytes to insert fragment header.
+ */
+ unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
+ nexthdr = *prevhdr;
+ *prevhdr = NEXTHDR_FRAGMENT;
+ unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
+ unfrag_ip6hlen;
+ mac_start = skb_mac_header(skb);
+ memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
+
+ skb->mac_header -= frag_hdr_sz;
+ skb->network_header -= frag_hdr_sz;
+
+ fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
+ fptr->nexthdr = nexthdr;
+ fptr->reserved = 0;
+ ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));
+
+ /* Fragment the skb. ipv6 header and the remaining fields of the
+ * fragment header are updated in ipv6_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+
+out:
+ return segs;
+}
+static const struct net_offload udpv6_offload = {
+ .gso_send_check = udp6_ufo_send_check,
+ .gso_segment = udp6_ufo_fragment,
+};
+
+int __init udp_offload_init(void)
+{
+ return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
+}
+
+void udp_offload_cleanup(void)
+{
+ inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
+}