net/sctp/offload.c

   1 /*
   2  * sctp_offload - GRO/GSO Offloading for SCTP
   3  *
   4  * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/kprobes.h>
  21 #include <linux/socket.h>
  22 #include <linux/sctp.h>
  23 #include <linux/proc_fs.h>
  24 #include <linux/vmalloc.h>
  25 #include <linux/module.h>
  26 #include <linux/kfifo.h>
  27 #include <linux/time.h>
  28 #include <net/net_namespace.h>
  29
  30 #include <linux/skbuff.h>
  31 #include <net/sctp/sctp.h>
  32 #include <net/sctp/checksum.h>
  33 #include <net/protocol.h>
  34
  35 static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
  36 {
  37         skb->ip_summed = CHECKSUM_NONE;
  38         return sctp_compute_cksum(skb, skb_transport_offset(skb));
  39 }
  40
  41 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
  42                                         netdev_features_t features)
  43 {
  44         struct sk_buff *segs = ERR_PTR(-EINVAL);
  45         struct sctphdr *sh;
  46
  47         sh = sctp_hdr(skb);
  48         if (!pskb_may_pull(skb, sizeof(*sh)))
  49                 goto out;
  50
  51         __skb_pull(skb, sizeof(*sh));
  52
  53         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
  54                 /* Packet is from an untrusted source, reset gso_segs. */
  55                 struct skb_shared_info *pinfo = skb_shinfo(skb);
  56                 struct sk_buff *frag_iter;
  57
  58                 pinfo->gso_segs = 0;
  59                 if (skb->len != skb->data_len) {
  60                         /* Means we have chunks in here too */
  61                         pinfo->gso_segs++;
  62                 }
  63
  64                 skb_walk_frags(skb, frag_iter)
  65                         pinfo->gso_segs++;
  66
  67                 segs = NULL;
  68                 goto out;
  69         }
  70
  71         segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
  72         if (IS_ERR(segs))
  73                 goto out;
  74
  75         /* All that is left is update SCTP CRC if necessary */
  76         if (!(features & NETIF_F_SCTP_CRC)) {
  77                 for (skb = segs; skb; skb = skb->next) {
  78                         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  79                                 sh = sctp_hdr(skb);
  80                                 sh->checksum = sctp_gso_make_checksum(skb);
  81                         }
  82                 }
  83         }
  84
  85 out:
  86         return segs;
  87 }
  88
  89 static const struct net_offload sctp_offload = {
  90         .callbacks = {
  91                 .gso_segment = sctp_gso_segment,
  92         },
  93 };
  94
  95 static const struct net_offload sctp6_offload = {
  96         .callbacks = {
  97                 .gso_segment = sctp_gso_segment,
  98         },
  99 };
 100
 101 int __init sctp_offload_init(void)
 102 {
 103         int ret;
 104
 105         ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
 106         if (ret)
 107                 goto out;
 108
 109         ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
 110         if (ret)
 111                 goto ipv4;
 112
 113         return ret;
 114
 115 ipv4:
 116         inet_del_offload(&sctp_offload, IPPROTO_SCTP);
 117 out:
 118         return ret;
 119 }