1 /* 2 * sctp_offload - GRO/GSO Offloading for SCTP 3 * 4 * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <linux/kernel.h> 20 #include <linux/kprobes.h> 21 #include <linux/socket.h> 22 #include <linux/sctp.h> 23 #include <linux/proc_fs.h> 24 #include <linux/vmalloc.h> 25 #include <linux/module.h> 26 #include <linux/kfifo.h> 27 #include <linux/time.h> 28 #include <net/net_namespace.h> 29 30 #include <linux/skbuff.h> 31 #include <net/sctp/sctp.h> 32 #include <net/sctp/checksum.h> 33 #include <net/protocol.h> 34 35 static __le32 sctp_gso_make_checksum(struct sk_buff *skb) 36 { 37 skb->ip_summed = CHECKSUM_NONE; 38 return sctp_compute_cksum(skb, skb_transport_offset(skb)); 39 } 40 41 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb, 42 netdev_features_t features) 43 { 44 struct sk_buff *segs = ERR_PTR(-EINVAL); 45 struct sctphdr *sh; 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 85 out: 86 return segs; 87 } 88 89 static const struct net_offload sctp_offload = { 90 .callbacks = { 91 .gso_segment = sctp_gso_segment, 92 }, 93 }; 94 95 static const struct net_offload sctp6_offload = { 96 .callbacks = { 97 .gso_segment = sctp_gso_segment, 98 }, 99 }; 100 101 int __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 return ret; 114 115 ipv4: 116 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 117 out: 118 return ret; 119 } 120