1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/errno.h> 3 #include <linux/ip.h> 4 #include <linux/kernel.h> 5 #include <linux/module.h> 6 #include <linux/skbuff.h> 7 #include <linux/socket.h> 8 #include <linux/types.h> 9 #include <net/checksum.h> 10 #include <net/ip.h> 11 #include <net/ip6_fib.h> 12 #include <net/lwtunnel.h> 13 #include <net/protocol.h> 14 #include <uapi/linux/ila.h> 15 #include "ila.h" 16 17 void ila_init_saved_csum(struct ila_params *p) 18 { 19 if (!p->locator_match.v64) 20 return; 21 22 p->csum_diff = compute_csum_diff8( 23 (__be32 *)&p->locator, 24 (__be32 *)&p->locator_match); 25 } 26 27 static __wsum get_csum_diff_iaddr(struct ila_addr *iaddr, struct ila_params *p) 28 { 29 if (p->locator_match.v64) 30 return p->csum_diff; 31 else 32 return compute_csum_diff8((__be32 *)&p->locator, 33 (__be32 *)&iaddr->loc); 34 } 35 36 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p) 37 { 38 return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p); 39 } 40 41 static void ila_csum_do_neutral_fmt(struct ila_addr *iaddr, 42 struct ila_params *p) 43 { 44 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3]; 45 __wsum diff, fval; 46 47 diff = get_csum_diff_iaddr(iaddr, p); 48 49 fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ? 50 CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG); 51 52 diff = csum_add(diff, fval); 53 54 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust))); 55 56 /* Flip the csum-neutral bit. Either we are doing a SIR->ILA 57 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method 58 * and the C-bit is not set, or we are doing an ILA-SIR 59 * tranlsation and the C-bit is set. 60 */ 61 iaddr->ident.csum_neutral ^= 1; 62 } 63 64 static void ila_csum_do_neutral_nofmt(struct ila_addr *iaddr, 65 struct ila_params *p) 66 { 67 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3]; 68 __wsum diff; 69 70 diff = get_csum_diff_iaddr(iaddr, p); 71 72 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust))); 73 } 74 75 static void ila_csum_adjust_transport(struct sk_buff *skb, 76 struct ila_params *p) 77 { 78 size_t nhoff = sizeof(struct ipv6hdr); 79 struct ipv6hdr *ip6h = ipv6_hdr(skb); 80 __wsum diff; 81 82 switch (ip6h->nexthdr) { 83 case NEXTHDR_TCP: 84 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) { 85 struct tcphdr *th = (struct tcphdr *) 86 (skb_network_header(skb) + nhoff); 87 88 ip6h = ipv6_hdr(skb); 89 diff = get_csum_diff(ip6h, p); 90 inet_proto_csum_replace_by_diff(&th->check, skb, 91 diff, true, true); 92 } 93 break; 94 case NEXTHDR_UDP: 95 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) { 96 struct udphdr *uh = (struct udphdr *) 97 (skb_network_header(skb) + nhoff); 98 99 if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) { 100 ip6h = ipv6_hdr(skb); 101 diff = get_csum_diff(ip6h, p); 102 inet_proto_csum_replace_by_diff(&uh->check, skb, 103 diff, true, true); 104 if (!uh->check) 105 uh->check = CSUM_MANGLED_0; 106 } 107 } 108 break; 109 case NEXTHDR_ICMP: 110 if (likely(pskb_may_pull(skb, 111 nhoff + sizeof(struct icmp6hdr)))) { 112 struct icmp6hdr *ih = (struct icmp6hdr *) 113 (skb_network_header(skb) + nhoff); 114 115 ip6h = ipv6_hdr(skb); 116 diff = get_csum_diff(ip6h, p); 117 inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb, 118 diff, true, true); 119 } 120 break; 121 } 122 } 123 124 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p, 125 bool sir2ila) 126 { 127 struct ipv6hdr *ip6h = ipv6_hdr(skb); 128 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr); 129 130 switch (p->csum_mode) { 131 case ILA_CSUM_ADJUST_TRANSPORT: 132 ila_csum_adjust_transport(skb, p); 133 /* 134 * ila_csum_adjust_transport() calls pskb_may_pull(), which can 135 * reallocate the skb head and leave ip6h (and the iaddr derived 136 * from it) dangling; reload both before the write below. The 137 * other csum modes do not pull, so their cached pointers stay 138 * valid. 139 */ 140 ip6h = ipv6_hdr(skb); 141 iaddr = ila_a2i(&ip6h->daddr); 142 break; 143 case ILA_CSUM_NEUTRAL_MAP: 144 if (sir2ila) { 145 if (WARN_ON(ila_csum_neutral_set(iaddr->ident))) { 146 /* Checksum flag should never be 147 * set in a formatted SIR address. 148 */ 149 break; 150 } 151 } else if (!ila_csum_neutral_set(iaddr->ident)) { 152 /* ILA to SIR translation and C-bit isn't 153 * set so we're good. 154 */ 155 break; 156 } 157 ila_csum_do_neutral_fmt(iaddr, p); 158 break; 159 case ILA_CSUM_NEUTRAL_MAP_AUTO: 160 ila_csum_do_neutral_nofmt(iaddr, p); 161 break; 162 case ILA_CSUM_NO_ACTION: 163 break; 164 } 165 166 /* Now change destination address */ 167 iaddr->loc = p->locator; 168 } 169