/*
 * 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;
	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;

	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,
	},
};

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;

	return ret;

ipv4:
	inet_del_offload(&sctp_offload, IPPROTO_SCTP);
out:
	return ret;
}
th'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&amp;id=39b3cfdd8814e0531a58cf074682d94066d75554'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/net?h=nds-private-remove&amp;id=39b3cfdd8814e0531a58cf074682d94066d75554'>net</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/openvswitch?h=nds-private-remove&amp;id=39b3cfdd8814e0531a58cf074682d94066d75554'>openvswitch</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/net/openvswitch?h=nds-private-remove&amp;id=39b3cfdd8814e0531a58cf074682d94066d75554&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=316d4d78cf9b6795b83f97c45368748741df418c'>openvswitch: Pack struct sw_flow_key.</a></td><td>Jarno Rajahalme</td><td>4</td><td><span class='deletions'>-34</span>/<span class='insertions'>+39</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=dd41d33f0b033885211a5d6f3ee19e73238aa9ee'>openvswitch: Add force commit.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+24</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=9dd7f8907c3705dc7a7a375d1c6e30b06e6daffc'>openvswitch: Add original direction conntrack tuple to sw_flow_key.</a></td><td>Jarno Rajahalme</td><td>7</td><td><span class='deletions'>-46</span>/<span class='insertions'>+227</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=09aa98ad496d6b11a698b258bc64d7f64c55d682'>openvswitch: Inherit master's labels.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-14</span>/<span class='insertions'>+31</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=6ffcea79957df43caeaa6d1de5062556a5afc262'>openvswitch: Refactor labels initialization.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-42</span>/<span class='insertions'>+62</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=b87cec3814ccc7f6afb0a1378ee7e5110d07cdd3'>openvswitch: Simplify labels length logic.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-11</span>/<span class='insertions'>+9</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=cb80d58fae76d8ea93555149b2b16e19b89a1f4f'>openvswitch: Unionize ovs_key_ct_label with a u32 array.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+8</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=193e30967897f3a8b6f9f137ac30571d832c2c5c'>openvswitch: Do not trigger events for unconfirmed connections.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-6</span>/<span class='insertions'>+22</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=9ff464db50e437eef131f719cc2e9902eea9c607'>openvswitch: Use inverted tuple in ovs_ct_find_existing() if NATted.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+22</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=5e17da634a21b1200853fe82ba67d6571f2beabe'>openvswitch: Fix comments for skb-&gt;_nfct</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+7</span></td></tr>
<tr><td><span title='2017-02-03 16:58:20 -0500'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=52e01b84a244473074fc0612c169e2e043d58b01'>Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next</a></td><td>David S. Miller</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+5</span></td></tr>
<tr><td><span title='2017-02-02 14:31:54 +0100'>2017-02-02</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=c74454fadd5ea6fc866ffe2c417a0dba56b2bf1c'>netfilter: add and use nf_ct_set helper</a></td><td>Florian Westphal</td><td>1</td><td><span class='deletions'>-4</span>/<span class='insertions'>+2</span></td></tr>
<tr><td><span title='2017-02-02 14:31:53 +0100'>2017-02-02</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=cb9c68363efb6d1f950ec55fb06e031ee70db5fc'>skbuff: add and use skb_nfct helper</a></td><td>Florian Westphal</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+3</span></td></tr>