net/sctp/offload.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * sctp_offload - GRO/GSO Offloading for SCTP
   4  *
   5  * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/kernel.h>
  11 #include <linux/kprobes.h>
  12 #include <linux/socket.h>
  13 #include <linux/sctp.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/module.h>
  17 #include <linux/kfifo.h>
  18 #include <linux/time.h>
  19 #include <net/net_namespace.h>
  20
  21 #include <linux/skbuff.h>
  22 #include <net/sctp/sctp.h>
  23 #include <net/sctp/checksum.h>
  24 #include <net/protocol.h>
  25
  26 static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
  27 {
  28         skb->ip_summed = CHECKSUM_NONE;
  29         skb->csum_not_inet = 0;
  30         gso_reset_checksum(skb, ~0);
  31         return sctp_compute_cksum(skb, skb_transport_offset(skb));
  32 }
  33
  34 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
  35                                         netdev_features_t features)
  36 {
  37         struct sk_buff *segs = ERR_PTR(-EINVAL);
  38         struct sctphdr *sh;
  39
  40         if (!skb_is_gso_sctp(skb))
  41                 goto out;
  42
  43         sh = sctp_hdr(skb);
  44         if (!pskb_may_pull(skb, sizeof(*sh)))
  45                 goto out;
  46
  47         __skb_pull(skb, sizeof(*sh));
  48
  49         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
  50                 /* Packet is from an untrusted source, reset gso_segs. */
  51                 struct skb_shared_info *pinfo = skb_shinfo(skb);
  52                 struct sk_buff *frag_iter;
  53
  54                 pinfo->gso_segs = 0;
  55                 if (skb->len != skb->data_len) {
  56                         /* Means we have chunks in here too */
  57                         pinfo->gso_segs++;
  58                 }
  59
  60                 skb_walk_frags(skb, frag_iter)
  61                         pinfo->gso_segs++;
  62
  63                 segs = NULL;
  64                 goto out;
  65         }
  66
  67         segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
  68         if (IS_ERR(segs))
  69                 goto out;
  70
  71         /* All that is left is update SCTP CRC if necessary */
  72         if (!(features & NETIF_F_SCTP_CRC)) {
  73                 for (skb = segs; skb; skb = skb->next) {
  74                         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  75                                 sh = sctp_hdr(skb);
  76                                 sh->checksum = sctp_gso_make_checksum(skb);
  77                         }
  78                 }
  79         }
  80
  81 out:
  82         return segs;
  83 }
  84
  85 static const struct net_offload sctp_offload = {
  86         .callbacks = {
  87                 .gso_segment = sctp_gso_segment,
  88         },
  89 };
  90
  91 static const struct net_offload sctp6_offload = {
  92         .callbacks = {
  93                 .gso_segment = sctp_gso_segment,
  94         },
  95 };
  96
  97 int __init sctp_offload_init(void)
  98 {
  99         int ret;
 100
 101         ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
 102         if (ret)
 103                 goto out;
 104
 105         ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
 106         if (ret)
 107                 goto ipv4;
 108
 109         crc32c_csum_stub = &sctp_csum_ops;
 110         return ret;
 111
 112 ipv4:
 113         inet_del_offload(&sctp_offload, IPPROTO_SCTP);
 114 out:
 115         return ret;
 116 }