1 #include <linux/errno.h> 2 #include <linux/ip.h> 3 #include <linux/kernel.h> 4 #include <linux/module.h> 5 #include <linux/skbuff.h> 6 #include <linux/socket.h> 7 #include <linux/types.h> 8 #include <net/checksum.h> 9 #include <net/ip.h> 10 #include <net/ip6_fib.h> 11 #include <net/lwtunnel.h> 12 #include <net/protocol.h> 13 #include <uapi/linux/ila.h> 14 #include "ila.h" 15 16 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p) 17 { 18 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr); 19 20 if (p->locator_match.v64) 21 return p->csum_diff; 22 else 23 return compute_csum_diff8((__be32 *)&iaddr->loc, 24 (__be32 *)&p->locator); 25 } 26 27 static void ila_csum_do_neutral(struct ila_addr *iaddr, 28 struct ila_params *p) 29 { 30 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3]; 31 __wsum diff, fval; 32 33 /* Check if checksum adjust value has been cached */ 34 if (p->locator_match.v64) { 35 diff = p->csum_diff; 36 } else { 37 diff = compute_csum_diff8((__be32 *)iaddr, 38 (__be32 *)&p->locator); 39 } 40 41 fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ? 42 ~CSUM_NEUTRAL_FLAG : CSUM_NEUTRAL_FLAG); 43 44 diff = csum_add(diff, fval); 45 46 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust))); 47 48 /* Flip the csum-neutral bit. Either we are doing a SIR->ILA 49 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method 50 * and the C-bit is not set, or we are doing an ILA-SIR 51 * tranlsation and the C-bit is set. 52 */ 53 iaddr->ident.csum_neutral ^= 1; 54 } 55 56 static void ila_csum_adjust_transport(struct sk_buff *skb, 57 struct ila_params *p) 58 { 59 __wsum diff; 60 struct ipv6hdr *ip6h = ipv6_hdr(skb); 61 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr); 62 size_t nhoff = sizeof(struct ipv6hdr); 63 64 switch (ip6h->nexthdr) { 65 case NEXTHDR_TCP: 66 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) { 67 struct tcphdr *th = (struct tcphdr *) 68 (skb_network_header(skb) + nhoff); 69 70 diff = get_csum_diff(ip6h, p); 71 inet_proto_csum_replace_by_diff(&th->check, skb, 72 diff, true); 73 } 74 break; 75 case NEXTHDR_UDP: 76 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) { 77 struct udphdr *uh = (struct udphdr *) 78 (skb_network_header(skb) + nhoff); 79 80 if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) { 81 diff = get_csum_diff(ip6h, p); 82 inet_proto_csum_replace_by_diff(&uh->check, skb, 83 diff, true); 84 if (!uh->check) 85 uh->check = CSUM_MANGLED_0; 86 } 87 } 88 break; 89 case NEXTHDR_ICMP: 90 if (likely(pskb_may_pull(skb, 91 nhoff + sizeof(struct icmp6hdr)))) { 92 struct icmp6hdr *ih = (struct icmp6hdr *) 93 (skb_network_header(skb) + nhoff); 94 95 diff = get_csum_diff(ip6h, p); 96 inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb, 97 diff, true); 98 } 99 break; 100 } 101 102 /* Now change destination address */ 103 iaddr->loc = p->locator; 104 } 105 106 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p) 107 { 108 struct ipv6hdr *ip6h = ipv6_hdr(skb); 109 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr); 110 111 /* First deal with the transport checksum */ 112 if (ila_csum_neutral_set(iaddr->ident)) { 113 /* C-bit is set in the locator indicating that this 114 * is a locator being translated to a SIR address. 115 * Perform (receiver) checksum-neutral translation. 116 */ 117 ila_csum_do_neutral(iaddr, p); 118 } else { 119 switch (p->csum_mode) { 120 case ILA_CSUM_ADJUST_TRANSPORT: 121 ila_csum_adjust_transport(skb, p); 122 break; 123 case ILA_CSUM_NEUTRAL_MAP: 124 ila_csum_do_neutral(iaddr, p); 125 break; 126 case ILA_CSUM_NO_ACTION: 127 break; 128 } 129 } 130 131 /* Now change destination address */ 132 iaddr->loc = p->locator; 133 } 134 135 void ila_init_saved_csum(struct ila_params *p) 136 { 137 if (!p->locator_match.v64) 138 return; 139 140 p->csum_diff = compute_csum_diff8( 141 (__be32 *)&p->locator_match, 142 (__be32 *)&p->locator); 143 } 144 145 static int __init ila_init(void) 146 { 147 int ret; 148 149 ret = ila_lwt_init(); 150 151 if (ret) 152 goto fail_lwt; 153 154 ret = ila_xlat_init(); 155 if (ret) 156 goto fail_xlat; 157 158 return 0; 159 fail_xlat: 160 ila_lwt_fini(); 161 fail_lwt: 162 return ret; 163 } 164 165 static void __exit ila_fini(void) 166 { 167 ila_xlat_fini(); 168 ila_lwt_fini(); 169 } 170 171 module_init(ila_init); 172 module_exit(ila_fini); 173 MODULE_ALIAS_RTNL_LWT(ILA); 174 MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>"); 175 MODULE_LICENSE("GPL"); 176