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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | // SPDX-License-Identifier: GPL-2.0 /* * xfrm4_input.c * * Changes: * YOSHIFUJI Hideaki @USAGI * Split up af-specific portion * Derek Atkins <derek@ihtfp.com> * Add Encapsulation support * */ #include <linux/slab.h> #include <linux/module.h> #include <linux/string.h> #include <linux/netfilter.h> #include <linux/netfilter_ipv4.h> #include <net/ip.h> #include <net/xfrm.h> static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk, struct sk_buff *skb) { return dst_input(skb); } static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { if (!skb_dst(skb)) { const struct iphdr *iph = ip_hdr(skb); if (ip_route_input_noref(skb, iph->daddr, iph->saddr, iph->tos, skb->dev)) goto drop; } if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2)) goto drop; return 0; drop: kfree_skb(skb); return NET_RX_DROP; } int xfrm4_transport_finish(struct sk_buff *skb, int async) { struct xfrm_offload *xo = xfrm_offload(skb); struct iphdr *iph = ip_hdr(skb); iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol; #ifndef CONFIG_NETFILTER if (!async) return -iph->protocol; #endif __skb_push(skb, skb->data - skb_network_header(skb)); iph->tot_len = htons(skb->len); ip_send_check(iph); if (xo && (xo->flags & XFRM_GRO)) { skb_mac_header_rebuild(skb); skb_reset_transport_header(skb); return 0; } NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, dev_net(skb->dev), NULL, skb, skb->dev, NULL, xfrm4_rcv_encap_finish); return 0; } /* If it's a keepalive packet, then just eat it. * If it's an encapsulated packet, then pass it to the * IPsec xfrm input. * Returns 0 if skb passed to xfrm or was dropped. * Returns >0 if skb should be passed to UDP. * Returns <0 if skb should be resubmitted (-ret is protocol) */ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) { struct udp_sock *up = udp_sk(sk); struct udphdr *uh; struct iphdr *iph; int iphlen, len; __u8 *udpdata; __be32 *udpdata32; __u16 encap_type = up->encap_type; /* if this is not encapsulated socket, then just return now */ if (!encap_type) return 1; /* If this is a paged skb, make sure we pull up * whatever data we need to look at. */ len = skb->len - sizeof(struct udphdr); if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) return 1; /* Now we can get the pointers */ uh = udp_hdr(skb); udpdata = (__u8 *)uh + sizeof(struct udphdr); udpdata32 = (__be32 *)udpdata; switch (encap_type) { default: case UDP_ENCAP_ESPINUDP: /* Check if this is a keepalive packet. If so, eat it. */ if (len == 1 && udpdata[0] == 0xff) { goto drop; } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { /* ESP Packet without Non-ESP header */ len = sizeof(struct udphdr); } else /* Must be an IKE packet.. pass it through */ return 1; break; case UDP_ENCAP_ESPINUDP_NON_IKE: /* Check if this is a keepalive packet. If so, eat it. */ if (len == 1 && udpdata[0] == 0xff) { goto drop; } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && udpdata32[0] == 0 && udpdata32[1] == 0) { /* ESP Packet with Non-IKE marker */ len = sizeof(struct udphdr) + 2 * sizeof(u32); } else /* Must be an IKE packet.. pass it through */ return 1; break; } /* At this point we are sure that this is an ESPinUDP packet, * so we need to remove 'len' bytes from the packet (the UDP * header and optional ESP marker bytes) and then modify the * protocol to ESP, and then call into the transform receiver. */ if (skb_unclone(skb, GFP_ATOMIC)) goto drop; /* Now we can update and verify the packet length... */ iph = ip_hdr(skb); iphlen = iph->ihl << 2; iph->tot_len = htons(ntohs(iph->tot_len) - len); if (skb->len < iphlen + len) { /* packet is too small!?! */ goto drop; } /* pull the data buffer up to the ESP header and set the * transport header to point to ESP. Keep UDP on the stack * for later. */ __skb_pull(skb, len); skb_reset_transport_header(skb); /* process ESP */ return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); drop: kfree_skb(skb); return 0; } int xfrm4_rcv(struct sk_buff *skb) { return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0); } EXPORT_SYMBOL(xfrm4_rcv); |