LXR linux/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
  26static __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
  34static 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
  81out:
  82        return segs;
  83}
  84
  85static const struct net_offload sctp_offload = {
  86        .callbacks = {
  87                .gso_segment = sctp_gso_segment,
  88        },
  89};
  90
  91static const struct net_offload sctp6_offload = {
  92        .callbacks = {
  93                .gso_segment = sctp_gso_segment,
  94        },
  95};
  96
  97int __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
 112ipv4:
 113        inet_del_offload(&sctp_offload, IPPROTO_SCTP);
 114out:
 115        return ret;
 116}
 117