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101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
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/*
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* IPV4 GSO/GRO offload support
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* Linux INET implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* UDPv4 GSO support
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*/
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#include <linux/skbuff.h>
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#include <net/udp.h>
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#include <net/protocol.h>
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static int udp4_ufo_send_check(struct sk_buff *skb)
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{
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if (!pskb_may_pull(skb, sizeof(struct udphdr)))
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return -EINVAL;
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if (likely(!skb->encapsulation)) {
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const struct iphdr *iph;
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struct udphdr *uh;
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iph = ip_hdr(skb);
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uh = udp_hdr(skb);
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uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
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IPPROTO_UDP, 0);
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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skb->ip_summed = CHECKSUM_PARTIAL;
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}
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return 0;
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}
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static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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unsigned int mss;
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mss = skb_shinfo(skb)->gso_size;
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if (unlikely(skb->len <= mss))
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goto out;
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
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/* Packet is from an untrusted source, reset gso_segs. */
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int type = skb_shinfo(skb)->gso_type;
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if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
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SKB_GSO_UDP_TUNNEL |
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SKB_GSO_GRE | SKB_GSO_MPLS) ||
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!(type & (SKB_GSO_UDP))))
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goto out;
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skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
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segs = NULL;
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goto out;
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}
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/* Fragment the skb. IP headers of the fragments are updated in
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* inet_gso_segment()
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*/
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if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
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segs = skb_udp_tunnel_segment(skb, features);
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else {
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int offset;
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__wsum csum;
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/* Do software UFO. Complete and fill in the UDP checksum as
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* HW cannot do checksum of UDP packets sent as multiple
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* IP fragments.
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*/
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offset = skb_checksum_start_offset(skb);
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csum = skb_checksum(skb, offset, skb->len - offset, 0);
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offset += skb->csum_offset;
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*(__sum16 *)(skb->data + offset) = csum_fold(csum);
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skb->ip_summed = CHECKSUM_NONE;
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segs = skb_segment(skb, features);
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}
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out:
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return segs;
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}
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static const struct net_offload udpv4_offload = {
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.callbacks = {
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.gso_send_check = udp4_ufo_send_check,
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.gso_segment = udp4_ufo_fragment,
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},
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};
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int __init udpv4_offload_init(void)
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{
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return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
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}
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