linux-stable/net/sctp/offload.c

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/*
* sctp_offload - GRO/GSO Offloading for SCTP
*
* Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/socket.h>
#include <linux/sctp.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/kfifo.h>
#include <linux/time.h>
#include <net/net_namespace.h>
#include <linux/skbuff.h>
#include <net/sctp/sctp.h>
#include <net/sctp/checksum.h>
#include <net/protocol.h>
static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
{
skb->ip_summed = CHECKSUM_NONE;
skb->csum_not_inet = 0;
sctp: call gso_reset_checksum when computing checksum in sctp_gso_segment Jianlin reported a panic when running sctp gso over gre over vlan device: [ 84.772930] RIP: 0010:do_csum+0x6d/0x170 [ 84.790605] Call Trace: [ 84.791054] csum_partial+0xd/0x20 [ 84.791657] gre_gso_segment+0x2c3/0x390 [ 84.792364] inet_gso_segment+0x161/0x3e0 [ 84.793071] skb_mac_gso_segment+0xb8/0x120 [ 84.793846] __skb_gso_segment+0x7e/0x180 [ 84.794581] validate_xmit_skb+0x141/0x2e0 [ 84.795297] __dev_queue_xmit+0x258/0x8f0 [ 84.795949] ? eth_header+0x26/0xc0 [ 84.796581] ip_finish_output2+0x196/0x430 [ 84.797295] ? skb_gso_validate_network_len+0x11/0x80 [ 84.798183] ? ip_finish_output+0x169/0x270 [ 84.798875] ip_output+0x6c/0xe0 [ 84.799413] ? ip_append_data.part.50+0xc0/0xc0 [ 84.800145] iptunnel_xmit+0x144/0x1c0 [ 84.800814] ip_tunnel_xmit+0x62d/0x930 [ip_tunnel] [ 84.801699] gre_tap_xmit+0xac/0xf0 [ip_gre] [ 84.802395] dev_hard_start_xmit+0xa5/0x210 [ 84.803086] sch_direct_xmit+0x14f/0x340 [ 84.803733] __dev_queue_xmit+0x799/0x8f0 [ 84.804472] ip_finish_output2+0x2e0/0x430 [ 84.805255] ? skb_gso_validate_network_len+0x11/0x80 [ 84.806154] ip_output+0x6c/0xe0 [ 84.806721] ? ip_append_data.part.50+0xc0/0xc0 [ 84.807516] sctp_packet_transmit+0x716/0xa10 [sctp] [ 84.808337] sctp_outq_flush+0xd7/0x880 [sctp] It was caused by SKB_GSO_CB(skb)->csum_start not set in sctp_gso_segment. sctp_gso_segment() calls skb_segment() with 'feature | NETIF_F_HW_CSUM', which causes SKB_GSO_CB(skb)->csum_start not to be set in skb_segment(). For TCP/UDP, when feature supports HW_CSUM, CHECKSUM_PARTIAL will be set and gso_reset_checksum will be called to set SKB_GSO_CB(skb)->csum_start. So SCTP should do the same as TCP/UDP, to call gso_reset_checksum() when computing checksum in sctp_gso_segment. Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-12 10:47:30 +00:00
gso_reset_checksum(skb, ~0);
return sctp_compute_cksum(skb, skb_transport_offset(skb));
}
static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct sctphdr *sh;
if (!skb_is_gso_sctp(skb))
goto out;
sh = sctp_hdr(skb);
if (!pskb_may_pull(skb, sizeof(*sh)))
goto out;
__skb_pull(skb, sizeof(*sh));
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
struct skb_shared_info *pinfo = skb_shinfo(skb);
struct sk_buff *frag_iter;
pinfo->gso_segs = 0;
if (skb->len != skb->data_len) {
/* Means we have chunks in here too */
pinfo->gso_segs++;
}
skb_walk_frags(skb, frag_iter)
pinfo->gso_segs++;
segs = NULL;
goto out;
}
segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
if (IS_ERR(segs))
goto out;
/* All that is left is update SCTP CRC if necessary */
if (!(features & NETIF_F_SCTP_CRC)) {
for (skb = segs; skb; skb = skb->next) {
if (skb->ip_summed == CHECKSUM_PARTIAL) {
sh = sctp_hdr(skb);
sh->checksum = sctp_gso_make_checksum(skb);
}
}
}
out:
return segs;
}
static const struct net_offload sctp_offload = {
.callbacks = {
.gso_segment = sctp_gso_segment,
},
};
static const struct net_offload sctp6_offload = {
.callbacks = {
.gso_segment = sctp_gso_segment,
},
};
static const struct skb_checksum_ops crc32c_csum_ops = {
.update = sctp_csum_update,
.combine = sctp_csum_combine,
};
int __init sctp_offload_init(void)
{
int ret;
ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
if (ret)
goto out;
ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
if (ret)
goto ipv4;
crc32c_csum_stub = &crc32c_csum_ops;
return ret;
ipv4:
inet_del_offload(&sctp_offload, IPPROTO_SCTP);
out:
return ret;
}