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 skb->csum_not_inet = 0; 39 return sctp_compute_cksum(skb, skb_transport_offset(skb)); 40 } 41 42 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb, 43 netdev_features_t features) 44 { 45 struct sk_buff *segs = ERR_PTR(-EINVAL); 46 struct sctphdr *sh; 47 48 sh = sctp_hdr(skb); 49 if (!pskb_may_pull(skb, sizeof(*sh))) 50 goto out; 51 52 __skb_pull(skb, sizeof(*sh)); 53 54 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 55 /* Packet is from an untrusted source, reset gso_segs. */ 56 struct skb_shared_info *pinfo = skb_shinfo(skb); 57 struct sk_buff *frag_iter; 58 59 pinfo->gso_segs = 0; 60 if (skb->len != skb->data_len) { 61 /* Means we have chunks in here too */ 62 pinfo->gso_segs++; 63 } 64 65 skb_walk_frags(skb, frag_iter) 66 pinfo->gso_segs++; 67 68 segs = NULL; 69 goto out; 70 } 71 72 segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG); 73 if (IS_ERR(segs)) 74 goto out; 75 76 /* All that is left is update SCTP CRC if necessary */ 77 if (!(features & NETIF_F_SCTP_CRC)) { 78 for (skb = segs; skb; skb = skb->next) { 79 if (skb->ip_summed == CHECKSUM_PARTIAL) { 80 sh = sctp_hdr(skb); 81 sh->checksum = sctp_gso_make_checksum(skb); 82 } 83 } 84 } 85 86 out: 87 return segs; 88 } 89 90 static const struct net_offload sctp_offload = { 91 .callbacks = { 92 .gso_segment = sctp_gso_segment, 93 }, 94 }; 95 96 static const struct net_offload sctp6_offload = { 97 .callbacks = { 98 .gso_segment = sctp_gso_segment, 99 }, 100 }; 101 102 static const struct skb_checksum_ops crc32c_csum_ops = { 103 .update = sctp_csum_update, 104 .combine = sctp_csum_combine, 105 }; 106 107 int __init sctp_offload_init(void) 108 { 109 int ret; 110 111 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP); 112 if (ret) 113 goto out; 114 115 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP); 116 if (ret) 117 goto ipv4; 118 119 crc32c_csum_stub = &crc32c_csum_ops; 120 return ret; 121 122 ipv4: 123 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 124 out: 125 return ret; 126 } 127