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 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP)) 49 goto out; 50 51 sh = sctp_hdr(skb); 52 if (!pskb_may_pull(skb, sizeof(*sh))) 53 goto out; 54 55 __skb_pull(skb, sizeof(*sh)); 56 57 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 58 /* Packet is from an untrusted source, reset gso_segs. */ 59 struct skb_shared_info *pinfo = skb_shinfo(skb); 60 struct sk_buff *frag_iter; 61 62 pinfo->gso_segs = 0; 63 if (skb->len != skb->data_len) { 64 /* Means we have chunks in here too */ 65 pinfo->gso_segs++; 66 } 67 68 skb_walk_frags(skb, frag_iter) 69 pinfo->gso_segs++; 70 71 segs = NULL; 72 goto out; 73 } 74 75 segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG); 76 if (IS_ERR(segs)) 77 goto out; 78 79 /* All that is left is update SCTP CRC if necessary */ 80 if (!(features & NETIF_F_SCTP_CRC)) { 81 for (skb = segs; skb; skb = skb->next) { 82 if (skb->ip_summed == CHECKSUM_PARTIAL) { 83 sh = sctp_hdr(skb); 84 sh->checksum = sctp_gso_make_checksum(skb); 85 } 86 } 87 } 88 89 out: 90 return segs; 91 } 92 93 static const struct net_offload sctp_offload = { 94 .callbacks = { 95 .gso_segment = sctp_gso_segment, 96 }, 97 }; 98 99 static const struct net_offload sctp6_offload = { 100 .callbacks = { 101 .gso_segment = sctp_gso_segment, 102 }, 103 }; 104 105 static const struct skb_checksum_ops crc32c_csum_ops = { 106 .update = sctp_csum_update, 107 .combine = sctp_csum_combine, 108 }; 109 110 int __init sctp_offload_init(void) 111 { 112 int ret; 113 114 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP); 115 if (ret) 116 goto out; 117 118 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP); 119 if (ret) 120 goto ipv4; 121 122 crc32c_csum_stub = &crc32c_csum_ops; 123 return ret; 124 125 ipv4: 126 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 127 out: 128 return ret; 129 } 130