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 *)&p->locator, 38 (__be32 *)iaddr); 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 bool set_csum_neutral) 108 { 109 struct ipv6hdr *ip6h = ipv6_hdr(skb); 110 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr); 111 112 /* First deal with the transport checksum */ 113 if (ila_csum_neutral_set(iaddr->ident)) { 114 /* C-bit is set in the locator indicating that this 115 * is a locator being translated to a SIR address. 116 * Perform (receiver) checksum-neutral translation. 117 */ 118 if (!set_csum_neutral) 119 ila_csum_do_neutral(iaddr, p); 120 } else { 121 switch (p->csum_mode) { 122 case ILA_CSUM_ADJUST_TRANSPORT: 123 ila_csum_adjust_transport(skb, p); 124 break; 125 case ILA_CSUM_NEUTRAL_MAP: 126 ila_csum_do_neutral(iaddr, p); 127 break; 128 case ILA_CSUM_NO_ACTION: 129 break; 130 } 131 } 132 133 /* Now change destination address */ 134 iaddr->loc = p->locator; 135 } 136 137 void ila_init_saved_csum(struct ila_params *p) 138 { 139 if (!p->locator_match.v64) 140 return; 141 142 p->csum_diff = compute_csum_diff8( 143 (__be32 *)&p->locator, 144 (__be32 *)&p->locator_match); 145 } 146 147 static int __init ila_init(void) 148 { 149 int ret; 150 151 ret = ila_lwt_init(); 152 153 if (ret) 154 goto fail_lwt; 155 156 ret = ila_xlat_init(); 157 if (ret) 158 goto fail_xlat; 159 160 return 0; 161 fail_xlat: 162 ila_lwt_fini(); 163 fail_lwt: 164 return ret; 165 } 166 167 static void __exit ila_fini(void) 168 { 169 ila_xlat_fini(); 170 ila_lwt_fini(); 171 } 172 173 module_init(ila_init); 174 module_exit(ila_fini); 175 MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>"); 176 MODULE_LICENSE("GPL"); 177