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 #include <net/gso.h> 26 27 static __le32 sctp_gso_make_checksum(struct sk_buff *skb) 28 { 29 skb->ip_summed = CHECKSUM_NONE; 30 skb->csum_not_inet = 0; 31 /* csum and csum_start in GSO CB may be needed to do the UDP 32 * checksum when it's a UDP tunneling packet. 33 */ 34 SKB_GSO_CB(skb)->csum = (__force __wsum)~0; 35 SKB_GSO_CB(skb)->csum_start = skb_headroom(skb) + skb->len; 36 return sctp_compute_cksum(skb, skb_transport_offset(skb)); 37 } 38 39 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb, 40 netdev_features_t features) 41 { 42 struct sk_buff *segs = ERR_PTR(-EINVAL); 43 struct sctphdr *sh; 44 45 if (!skb_is_gso_sctp(skb)) 46 goto out; 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 int __init sctp_offload_init(void) 103 { 104 int ret; 105 106 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP); 107 if (ret) 108 goto out; 109 110 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP); 111 if (ret) 112 goto ipv4; 113 114 crc32c_csum_stub = &sctp_csum_ops; 115 return ret; 116 117 ipv4: 118 inet_del_offload(&sctp_offload, IPPROTO_SCTP); 119 out: 120 return ret; 121 } 122