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 gso_reset_checksum(skb, ~0); 40 return sctp_compute_cksum(skb, skb_transport_offset(skb)); 41 } 42 43 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb, 44 netdev_features_t features) 45 { 46 struct sk_buff *segs = ERR_PTR(-EINVAL); 47 struct sctphdr *sh; 48 49 if (!skb_is_gso_sctp(skb)) 50 goto out; 51 52 sh = sctp_hdr(skb); 53 if (!pskb_may_pull(skb, sizeof(*sh))) 54 goto out; 55 56 __skb_pull(skb, sizeof(*sh)); 57 58 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 59 /* Packet is from an untrusted source, reset gso_segs. */ 60 struct skb_shared_info *pinfo = skb_shinfo(skb); 61 struct sk_buff *frag_iter; 62 63 pinfo->gso_segs = 0; 64 if (skb->len != skb->data_len) { 65 /* Means we have chunks in here too */ 66 pinfo->gso_segs++; 67 } 68 69 skb_walk_frags(skb, frag_iter) 70 pinfo->gso_segs++; 71 72 segs = NULL; 73 goto out; 74 } 75 76 segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG); 77 if (IS_ERR(segs)) 78 goto out; 79 80 /* All that is left is update SCTP CRC if necessary */ 81 if (!(features & NETIF_F_SCTP_CRC)) { 82 for (skb = segs; skb; skb = skb->next) { 83 if (skb->ip_summed == CHECKSUM_PARTIAL) { 84 sh = sctp_hdr(skb); 85 sh->checksum = sctp_gso_make_checksum(skb); 86 } 87 } 88 } 89 90 out: 91 return segs; 92 } 93 94 static const struct net_offload sctp_offload = { 95 .callbacks = { 96 .gso_segment = sctp_gso_segment, 97 }, 98 }; 99 100 static const struct net_offload sctp6_offload = { 101 .callbacks = { 102 .gso_segment = sctp_gso_segment, 103 }, 104 }; 105 106 static const struct skb_checksum_ops crc32c_csum_ops = { 107 .update = sctp_csum_update, 108 .combine = sctp_csum_combine, 109 }; 110 111 int __init sctp_offload_init(void) 112 { 113 int ret; 114 115 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP); 116 if (ret) 117 goto out; 118 119 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP); 120 if (ret) 121 goto ipv4; 122 123 crc32c_csum_stub = &crc32c_csum_ops; 124 return ret; 125 126 ipv4: 127 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 128 out: 129 return ret; 130 } 131