1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * sctp_offload - GRO/GSO Offloading for SCTP 4 * 5 * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/kernel.h> 11 #include <linux/kprobes.h> 12 #include <linux/socket.h> 13 #include <linux/sctp.h> 14 #include <linux/proc_fs.h> 15 #include <linux/vmalloc.h> 16 #include <linux/module.h> 17 #include <linux/kfifo.h> 18 #include <linux/time.h> 19 #include <net/net_namespace.h> 20 21 #include <linux/skbuff.h> 22 #include <net/sctp/sctp.h> 23 #include <net/sctp/checksum.h> 24 #include <net/protocol.h> 25 26 static __le32 sctp_gso_make_checksum(struct sk_buff *skb) 27 { 28 skb->ip_summed = CHECKSUM_NONE; 29 skb->csum_not_inet = 0; 30 /* csum and csum_start in GSO CB may be needed to do the UDP 31 * checksum when it's a UDP tunneling packet. 32 */ 33 SKB_GSO_CB(skb)->csum = (__force __wsum)~0; 34 SKB_GSO_CB(skb)->csum_start = skb_headroom(skb) + skb->len; 35 return sctp_compute_cksum(skb, skb_transport_offset(skb)); 36 } 37 38 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb, 39 netdev_features_t features) 40 { 41 struct sk_buff *segs = ERR_PTR(-EINVAL); 42 struct sctphdr *sh; 43 44 if (!skb_is_gso_sctp(skb)) 45 goto out; 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 crc32c_csum_stub = &sctp_csum_ops; 114 return ret; 115 116 ipv4: 117 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 118 out: 119 return ret; 120 } 121