/* * 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;	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,	},}; 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;}