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        /* 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
  38static 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
  85out:
  86        return segs;
  87}
  88
  89static const struct net_offload sctp_offload = {
  90        .callbacks = {
  91                .gso_segment = sctp_gso_segment,
  92        },
  93};
  94
  95static const struct net_offload sctp6_offload = {
  96        .callbacks = {
  97                .gso_segment = sctp_gso_segment,
  98        },
  99};
 100
 101int __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
 116ipv4:
 117        inet_del_offload(&sctp_offload, IPPROTO_SCTP);
 118out:
 119        return ret;
 120}
 121