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         /* csum and csum_start in GSO CB may be needed to do the UDP
  31          * checksum when it's a UDP tunneling packet.
  32          */
  33         SKB_GSO_CB(skb)->csum = (__force __wsum)~0;
  34         SKB_GSO_CB(skb)->csum_start = skb_headroom(skb) + skb->len;
  35         return sctp_compute_cksum(skb, skb_transport_offset(skb));
  36 }
  37
  38 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
  39                                         netdev_features_t features)
  40 {
  41         struct sk_buff *segs = ERR_PTR(-EINVAL);
  42         struct sctphdr *sh;
  43
  44         if (!skb_is_gso_sctp(skb))
  45                 goto out;
  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         crc32c_csum_stub = &sctp_csum_ops;
 114         return ret;
 115
 116 ipv4:
 117         inet_del_offload(&sctp_offload, IPPROTO_SCTP);
 118 out:
 119         return ret;
 120 }