// SPDX-License-Identifier: GPL-2.0-only /* * Network Service Header * * Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com> */ #include <linux/module.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/nsh.h> #include <net/tun_proto.h> int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh) { struct nshhdr *nh; size_t length = nsh_hdr_len(pushed_nh); u8 next_proto; if (skb->mac_len) { next_proto = TUN_P_ETHERNET; } else { next_proto = tun_p_from_eth_p(skb->protocol); if (!next_proto) return -EAFNOSUPPORT; } /* Add the NSH header */ if (skb_cow_head(skb, length) < 0) return -ENOMEM; skb_push(skb, length); nh = (struct nshhdr *)(skb->data); memcpy(nh, pushed_nh, length); nh->np = next_proto; skb_postpush_rcsum(skb, nh, length); skb->protocol = htons(ETH_P_NSH); skb_reset_mac_header(skb); skb_reset_network_header(skb); skb_reset_mac_len(skb); return 0; } EXPORT_SYMBOL_GPL(nsh_push); int nsh_pop(struct sk_buff *skb) { struct nshhdr *nh; size_t length; __be16 inner_proto; if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN)) return -ENOMEM; nh = (struct nshhdr *)(skb->data); length = nsh_hdr_len(nh); if (length < NSH_BASE_HDR_LEN) return -EINVAL; inner_proto = tun_p_to_eth_p(nh->np); if (!pskb_may_pull(skb, length)) return -ENOMEM; if (!inner_proto) return -EAFNOSUPPORT; skb_pull_rcsum(skb, length); skb_reset_mac_header(skb); skb_reset_network_header(skb); skb_reset_mac_len(skb); skb->protocol = inner_proto; return 0; } EXPORT_SYMBOL_GPL(nsh_pop); static struct sk_buff *nsh_gso_segment(struct sk_buff *skb, netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); unsigned int nsh_len, mac_len; __be16 proto; int nhoff; skb_reset_network_header(skb); nhoff = skb->network_header - skb->mac_header; mac_len = skb->mac_len; if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN))) goto out; nsh_len = nsh_hdr_len(nsh_hdr(skb)); if (nsh_len < NSH_BASE_HDR_LEN) goto out; if (unlikely(!pskb_may_pull(skb, nsh_len))) goto out; proto = tun_p_to_eth_p(nsh_hdr(skb)->np); if (!proto) goto out; __skb_pull(skb, nsh_len); skb_reset_mac_header(skb); skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0; skb->protocol = proto; features &= NETIF_F_SG; segs = skb_mac_gso_segment(skb, features); if (IS_ERR_OR_NULL(segs)) { skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len, skb->network_header - nhoff, mac_len); goto out; } for (skb = segs; skb; skb = skb->next) { skb->protocol = htons(ETH_P_NSH); __skb_push(skb, nsh_len); skb_set_mac_header(skb, -nhoff); skb->network_header = skb->mac_header + mac_len; skb->mac_len = mac_len; } out: return segs; } static struct packet_offload nsh_packet_offload __read_mostly = { .type = htons(ETH_P_NSH), .priority = 15, .callbacks = { .gso_segment = nsh_gso_segment, }, }; static int __init nsh_init_module(void) { dev_add_offload(&nsh_packet_offload); return 0; } static void __exit nsh_cleanup_module(void) { dev_remove_offload(&nsh_packet_offload); } module_init(nsh_init_module); module_exit(nsh_cleanup_module); MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>"); MODULE_DESCRIPTION("NSH protocol"); MODULE_LICENSE("GPL v2");