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-rw-r--r--src/roms/SLOF/clients/net-snk/app/netlib/ipv6.c768
1 files changed, 768 insertions, 0 deletions
diff --git a/src/roms/SLOF/clients/net-snk/app/netlib/ipv6.c b/src/roms/SLOF/clients/net-snk/app/netlib/ipv6.c
new file mode 100644
index 0000000..0cb0a2e
--- /dev/null
+++ b/src/roms/SLOF/clients/net-snk/app/netlib/ipv6.c
@@ -0,0 +1,768 @@
+/******************************************************************************
+ * Copyright (c) 2013 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ * IBM Corporation - initial implementation
+ *****************************************************************************/
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <ctype.h>
+#include <sys/socket.h>
+#include <netlib/ethernet.h>
+#include <netlib/ipv6.h>
+#include <netlib/icmpv6.h>
+#include <netlib/ndp.h>
+#include <netlib/udp.h>
+
+#undef IPV6_DEBUG
+//#define IPV6_DEBUG
+#ifdef IPV6_DEBUG
+#define dprintf(_x ...) do { printf(_x); } while (0)
+#else
+#define dprintf(_x ...)
+#endif
+
+/****************************** PROTOTYPES *******************************/
+int8_t ip6addr_add (struct ip6addr_list_entry *new_address);
+static void ipv6_init(int fd);
+static int ip6_is_multicast (ip6_addr_t * ip);
+
+/****************************** LOCAL VARIABLES **************************/
+
+/* Own IPv6 address */
+static struct ip6addr_list_entry *own_ip6;
+
+/* Null IPv6 address */
+static ip6_addr_t null_ip6;
+
+/* helper variables */
+static uint8_t null_mac[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+
+/****************************** IMPLEMENTATION ***************************/
+
+/**
+ * IPv6: Set the own IPv6 address.
+ *
+ * @param fd Socket descriptor
+ * @param _own_ip client IPv6 address (e.g. ::1)
+ */
+void
+set_ipv6_address (int fd, ip6_addr_t *_own_ip6)
+{
+ own_ip6 = malloc (sizeof(struct ip6addr_list_entry));
+
+ /* If no address was passed as a parameter generate a link-local
+ * address from our MAC address.*/
+ if (_own_ip6 == NULL)
+ memcpy(&(own_ip6->addr.addr),
+ ip6_create_ll_address(get_mac_address()),
+ IPV6_ADDR_LENGTH);
+ else
+ memcpy (&(own_ip6->addr.addr), _own_ip6, 16);
+
+ /* Add to our list of IPv6 addresses */
+ ip6addr_add (own_ip6);
+
+ ipv6_init(fd);
+}
+
+/**
+ * IPv6: Get pointer to own IPv6 address.
+ *
+ * @return pointer to client IPv6 address (e.g. ::1)
+ */
+ip6_addr_t *
+get_ipv6_address (void)
+{
+ return (ip6_addr_t *) &(own_ip6->addr);
+}
+
+/**
+ * IPv6: Search for IPv6 address in list
+ *
+ * @return 0 - IPv6 address is not in list
+ * 1 - IPv6 address is in list
+ */
+static int8_t
+find_ip6addr (ip6_addr_t *ip)
+{
+ struct ip6addr_list_entry *n = NULL;
+
+ if (ip == NULL)
+ return 0;
+
+ for (n = first_ip6; n != NULL ; n=n->next)
+ if (ip6_cmp (&(n->addr), ip))
+ return 1; /* IPv6 address is in our list*/
+
+ return 0; /* not one of our IPv6 addresses*/
+}
+
+/**
+ * NET: Handles IPv6-packets
+ *
+ * @param fd - Socket descriptor
+ * @param ip6_packet - Pointer to IPv6 header
+ * @param packetsize - Size of Ipv6 packet
+ * @return ERROR - -1 if packet is too small or unknown protocol
+ * return value of handle_udp
+ *
+ * @see handle_udp
+ * @see ip6hdr
+ */
+int8_t
+handle_ipv6 (int fd, uint8_t * ip6_packet, int32_t packetsize)
+{
+
+ struct ip6hdr *ip6 = NULL;
+ ip6 = (struct ip6hdr *) ip6_packet;
+
+ /* Only handle packets which are for us */
+ if (! find_ip6addr(&(ip6->dst)))
+ return -1;
+
+ if (packetsize < sizeof(struct ip6hdr))
+ return -1; // packet is too small
+
+ switch (ip6->nh) {
+ case IPTYPE_UDP:
+ return handle_udp (fd, ip6_packet + sizeof (struct ip6hdr),
+ ip6->pl);
+ case IPTYPE_ICMPV6:
+ return handle_icmpv6 (fd, (struct ethhdr *) ip6_packet - sizeof(struct ethhdr),
+ ip6_packet);
+ }
+
+ return -1; // unknown protocol
+}
+
+ /**
+ * NET: Creates IPv6-packet. Places IPv6-header in a packet and fills it
+ * with corresponding information.
+ * <p>
+ * Use this function with similar functions for other network layers
+ * (fill_ethhdr, fill_udphdr, fill_dnshdr, fill_btphdr).
+ *
+ * @param packet Points to the place where IPv6-header must be placed.
+ * @param packetsize Size of payload (i.e. excluding ethhdr and ip6hdr)
+ * @param ip_proto Type of the next level protocol (e.g. UDP).
+ * @param ip6_src Sender IPv6 address
+ * @param ip6_dst Receiver IPv6 address
+ * @see ip6hdr
+ * @see fill_iphdr
+ * @see fill_ethhdr
+ * @see fill_udphdr
+ * @see fill_dnshdr
+ * @see fill_btphdr
+ */
+void
+fill_ip6hdr (uint8_t * packet, uint16_t packetsize,
+ uint8_t ip_proto, ip6_addr_t *ip6_src, ip6_addr_t *ip6_dst)
+{
+
+ struct ip6hdr * ip6h = (struct ip6hdr *) packet;
+
+ ip6h->ver_tc_fl = 6 << 28; // set version to 6
+ ip6h->pl = packetsize; // IPv6 payload size
+ ip6h->nh = ip_proto;
+ ip6h->hl = 255;
+ memcpy (&(ip6h->src), ip6_src, IPV6_ADDR_LENGTH);
+ memcpy (&(ip6h->dst), ip6_dst, IPV6_ADDR_LENGTH);
+}
+
+/**
+ * NET: For a given MAC calculates EUI64-Identifier.
+ * See RFC 4291 "IP Version 6 Addressing Architecture"
+ *
+ */
+uint64_t
+mac2eui64 (const uint8_t *mac)
+{
+ uint8_t eui64id[8];
+ uint64_t retid;
+
+ memcpy (eui64id, mac, 3);
+ memcpy (eui64id + 5, mac + 3, 3);
+ eui64id[3] = 0xff;
+ eui64id[4] = 0xfe;
+
+ memcpy(&retid, eui64id, 8);
+ return retid;
+}
+
+/**
+ * NET: create link-local IPv6 address
+ *
+ * @param own_mac MAC of NIC
+ * @return ll_addr pointer to newly created link-local address
+ */
+ip6_addr_t *
+ip6_create_ll_address (const uint8_t *own_mac)
+{
+ ip6_addr_t *ll_addr;
+
+ ll_addr = malloc (sizeof (struct ip6addr_list_entry));
+ memset (ll_addr, 0, IPV6_ADDR_LENGTH);
+ ll_addr->part.prefix |= IPV6_LL_PREFIX;
+ ll_addr->part.interface_id |= mac2eui64((uint8_t *) own_mac);
+
+ return ll_addr;
+}
+
+/*
+ * NET: check if we already have an address with the same prefix.
+ * @param struct ip6_addr_list_entry *ip6
+ * @return true or false
+ */
+int8_t
+unknown_prefix (ip6_addr_t *ip)
+{
+ struct ip6addr_list_entry *node;
+
+ for( node = first_ip6; node != NULL; node=node->next )
+ if( node->addr.part.prefix == ip->part.prefix )
+ return 0; /* address is one of ours */
+
+ return 1; /* prefix not yet in our list */
+}
+
+/*
+ * NET: Create empty element for prefix list and return a pointer to it;
+ * @return NULL - malloc failed
+ * ! NULL - pointer to new prefix_info
+ */
+struct prefix_info *
+ip6_create_prefix_info ()
+{
+ struct prefix_info *prfx_info;
+
+ prfx_info = malloc (sizeof(struct prefix_info));
+ if (!prfx_info)
+ return NULL;
+
+ return prfx_info;
+}
+
+/*
+ * NET: create a new IPv6 address with a given network prefix
+ * and add it to our IPv6 address list
+ *
+ * @param ip6_addr prefix (as received in RA)
+ * @return NULL - pointer to new ip6addr_list entry
+ */
+void *
+ip6_prefix2addr (ip6_addr_t prefix)
+{
+ struct ip6addr_list_entry *new_address;
+ uint64_t interface_id;
+
+ new_address = malloc (sizeof(struct ip6addr_list_entry));
+ if( !new_address )
+ return NULL;
+
+ /* fill new addr struct */
+ /* extract prefix from Router Advertisement */
+ memcpy (&(new_address->addr.part.prefix), &prefix, 8 );
+
+ /* interface id is generated from MAC address */
+ interface_id = mac2eui64 (get_mac_address());
+ memcpy (&(new_address->addr.part.interface_id), &interface_id, 8);
+
+ return new_address;
+}
+
+/**
+ * NET: add new IPv6 adress to list
+ *
+ * @param ip6_addr *new_address
+ * @return 0 - passed pointer = NULL;
+ * 1 - ok
+ */
+int8_t
+ip6addr_add (struct ip6addr_list_entry *new_address)
+{
+ struct ip6addr_list_entry *solicited_node;
+
+
+ if (new_address == NULL)
+ return 0;
+
+ /* Don't add the same address twice */
+ if (find_ip6addr (&(new_address->addr)))
+ return 0;
+
+ /* If address is a unicast address, we also have to process packets
+ * for its solicited-node multicast address.
+ * See RFC 2373 - IP Version 6 Adressing Architecture */
+ if (! ip6_is_multicast(&(new_address->addr))) {
+
+
+ solicited_node = malloc(sizeof(struct ip6addr_list_entry));
+ if (! solicited_node)
+ return 0;
+
+ solicited_node->addr.part.prefix = IPV6_SOLIC_NODE_PREFIX;
+ solicited_node->addr.part.interface_id = IPV6_SOLIC_NODE_IFACE_ID;
+ solicited_node->addr.addr[13] = new_address->addr.addr[13];
+ solicited_node->addr.addr[14] = new_address->addr.addr[14];
+ solicited_node->addr.addr[15] = new_address->addr.addr[15];
+ ip6addr_add (solicited_node);
+ }
+
+ if (NULL == first_ip6)
+ first_ip6 = new_address;
+ last_ip6->next = new_address;
+ last_ip6 = new_address;
+ last_ip6->next = NULL;
+
+ return 1; /* no error */
+}
+
+/**
+ * NET: Initialize IPv6
+ *
+ * @param fd socket fd
+ */
+static void
+ipv6_init (int fd)
+{
+ int i = 0;
+
+ send_ip = &send_ipv6;
+
+ /* Address configuration parameters */
+ ip6_state.managed_mode = 0;
+
+ /* Null IPv6 address */
+ null_ip6.part.prefix = 0;
+ null_ip6.part.interface_id = 0;
+
+ /* Multicast addresses */
+ all_nodes_ll.addr.part.prefix = 0xff02000000000000;
+ all_nodes_ll.addr.part.interface_id = 1;
+ all_dhcpv6_ll.addr.part.prefix = 0xff02000000000000ULL;
+ all_dhcpv6_ll.addr.part.interface_id = 0x10002ULL;
+ all_routers_ll.addr.part.prefix = 0xff02000000000000;
+ all_routers_ll.addr.part.interface_id = 2;
+
+ ip6addr_add(&all_nodes_ll);
+ /* ... */
+
+ /* Router list */
+ first_router = NULL;
+ last_router = first_router;
+
+ /* Init Neighbour cache */
+ first_neighbor = NULL;
+ last_neighbor = first_neighbor;
+
+ send_router_solicitation (fd);
+ for(i=0; i < 4 && !is_ra_received(); i++) {
+ set_timer(TICKS_SEC);
+ do {
+ receive_ether(fd);
+ if (is_ra_received())
+ break;
+ } while (get_timer() > 0);
+ }
+}
+
+/**
+ * NET: compare IPv6 adresses
+ *
+ * @param ip6_addr ip_1
+ * @param ip6_addr ip_2
+ */
+int8_t
+ip6_cmp (ip6_addr_t *ip_1, ip6_addr_t *ip_2)
+{
+ return ((int8_t) !memcmp( &(ip_1->addr[0]), &(ip_2->addr[0]),
+ IPV6_ADDR_LENGTH ));
+}
+
+/**
+ * NET: Calculate checksum over IPv6 header and upper-layer protocol
+ * (e.g. UDP or ICMPv6)
+ *
+ * @param *ip - pointer to IPv6 address
+ * @return true or false
+ */
+int
+ip6_is_multicast (ip6_addr_t * ip)
+{
+ uint8_t mc = 0xFF;
+ return ! memcmp(&ip->addr[0], &mc, 1);
+}
+
+/**
+ * NET: Generate multicast MAC address from IPv6 address
+ * (e.g. UDP or ICMPv6)
+ *
+ * @param *ip - pointer to IPv6 address
+ * @return pointer to Multicast MAC address
+ */
+static uint8_t *
+ip6_to_multicast_mac (ip6_addr_t * ip)
+{
+ uint8_t *mc_mac;
+
+ mc_mac = malloc(ETH_ALEN);
+ if (!mc_mac)
+ return NULL;
+
+ mc_mac[0] = 0x33;
+ mc_mac[1] = 0x33;
+ memcpy (mc_mac+2, (uint8_t *) &(ip->addr)+12, 4);
+
+ return mc_mac;
+}
+
+/**
+ * NET: calculate checksum over IPv6 header and upper-layer protocol
+ * (e.g. UDP or ICMPv6)
+ *
+ * @param struct ip6hdr *ip6h - pointer to IPv6 header
+ * @param unsigned short *packet - pointer to header of upper-layer
+ * protocol
+ * @param int words - number of words (as in 2 bytes)
+ * starting from *packet
+ * @return checksum
+ */
+static unsigned short
+ip6_checksum (struct ip6hdr *ip6h, unsigned short *packet, int words)
+{
+ int i=0;
+ unsigned long checksum;
+ struct ip6hdr pseudo_ip6h;
+ unsigned short *pip6h;
+
+ memcpy (&pseudo_ip6h, ip6h, sizeof(struct ip6hdr));
+ pseudo_ip6h.hl = ip6h->nh;
+ pseudo_ip6h.ver_tc_fl = 0;
+ pseudo_ip6h.nh = 0;
+ pip6h = (unsigned short *) &pseudo_ip6h;
+
+ for (checksum = 0; words > 0; words--) {
+ checksum += *packet++;
+ i++;
+ }
+
+ for (i = 0; i < 20; i++) {
+ checksum += *pip6h++;
+ }
+
+ checksum = (checksum >> 16) + (checksum & 0xffff);
+ checksum += (checksum >> 16);
+
+ return ~checksum;
+}
+
+/**
+ * NET: Handles IPv6-packets
+ *
+ * @param fd socket fd
+ * @param ip6_packet Pointer to IPv6 header in packet
+ * @param packetsize Size of IPv6 packet
+ * @return -1 == ERRROR
+ * return of handle_udp() or handle_icmp6()
+ *
+ * @see receive_ether
+ * @see ip6hdr
+ */
+int
+send_ipv6 (int fd, void* buffer, int len)
+{
+ struct neighbor *n;
+ struct ip6hdr *ip6h;
+ struct udphdr *udph;
+ struct icmp6hdr *icmp6h;
+ ip6_addr_t ip_dst;
+ uint8_t *mac_addr, mac[6];
+
+ mac_addr = mac;
+
+ ip6h = (struct ip6hdr *) buffer;
+ udph = (struct udphdr *) ((uint8_t *) ip6h + sizeof (struct ip6hdr));
+ icmp6h = (struct icmp6hdr *) ((uint8_t *) ip6h + sizeof (struct ip6hdr));
+
+ memcpy(&ip_dst, &ip6h->dst, 16);
+
+ if(len + sizeof(struct ethhdr) > 1500)
+ return -1;
+
+ if ( ip6_cmp (&ip6h->src, &null_ip6))
+ memcpy (&(ip6h->src), get_ipv6_address(), IPV6_ADDR_LENGTH);
+
+ if (ip6h->nh == 17) {//UDP
+ udph->uh_sum = ip6_checksum (ip6h, (unsigned short *) udph ,
+ ip6h->pl >> 1);
+ /* As per RFC 768, if the computed checksum is zero,
+ * it is transmitted as all ones (the equivalent in
+ * one's complement arithmetic).
+ */
+ if (udph->uh_sum == 0)
+ udph->uh_sum = ~udph->uh_sum;
+ }
+ else if (ip6h->nh == 0x3a) //ICMPv6
+ icmp6h->checksum = ip6_checksum (ip6h,
+ (unsigned short *) icmp6h,
+ ip6h->pl >> 1);
+
+ n = find_neighbor (&ip_dst);
+
+ // If packet is a neighbor solicitation
+ if (icmp6h->type == ICMPV6_NEIGHBOUR_SOLICITATION) {
+ mac_addr = ip6_to_multicast_mac (&ip_dst);
+ fill_ethhdr( buffer-sizeof(struct ethhdr), htons(ETHERTYPE_IPv6),
+ get_mac_address(),
+ mac_addr);
+ }
+
+ // If address is a multicast address, create a proper mac address
+ else if (ip6_is_multicast (&ip_dst)) {
+ mac_addr = ip6_to_multicast_mac (&ip_dst);
+ }
+ else {
+ // Check if the MAC address is already cached
+ if (n) {
+ if (memcmp(n->mac, null_mac, ETH_ALEN) != 0)
+ memcpy (mac_addr, &(n->mac), ETH_ALEN); /* found it */
+ } else {
+ mac_addr = null_mac;
+ n = malloc(sizeof(struct neighbor));
+ memcpy(&(n->ip.addr[0]), &ip_dst, 16);
+ n->status = NB_PROBE;
+ n->times_asked += 1;
+ neighbor_add(n);
+ }
+
+ if (! memcmp (mac_addr, &null_mac, 6)) {
+ if (n->eth_len == 0) {
+ send_neighbour_solicitation (fd, &ip_dst);
+
+ // Store the packet until we know the MAC address
+ memset(n->eth_frame, 0, 1500);
+ fill_ethhdr (n->eth_frame,
+ htons(ETHERTYPE_IPv6),
+ get_mac_address(),
+ mac_addr);
+ memcpy (&(n->eth_frame[sizeof(struct ethhdr)]),
+ buffer, len);
+ n->eth_len = len;
+ set_timer(TICKS_SEC);
+ do {
+ receive_ether(fd);
+ } while (get_timer() > 0);
+ }
+ }
+ }
+
+ fill_ethhdr (n->eth_frame, htons(ETHERTYPE_IPv6), get_mac_address(),
+ mac_addr);
+ memcpy (&(n->eth_frame[sizeof(struct ethhdr)]), buffer, len);
+ return send_ether (fd, n->eth_frame, len + sizeof(struct ethhdr));
+}
+
+static int
+check_colons(const char *str)
+{
+ char *pch, *prv;
+ int col = 0;
+ int dcol = 0;
+
+ dprintf("str : %s\n",str);
+ pch = strchr(str, ':');
+ while(pch != NULL){
+ prv = pch;
+ pch = strchr(pch+1, ':');
+ if((pch-prv) != 1) {
+ col++;
+ } else {
+ col--; /* Its part of double colon */
+ dcol++;
+ }
+ }
+
+ dprintf("The number of col : %d \n",col);
+ dprintf("The number of dcol : %d \n",dcol);
+
+ if((dcol > 1) || /* Cannot have 2 "::" */
+ ((dcol == 1) && (col > 5)) || /* Too many ':'s */
+ ((dcol == 0) && (col != 7)) ) { /* Too few ':'s */
+ dprintf(" exiting for check_colons \n");
+ return 0;
+ }
+
+ return (col+dcol);
+}
+
+static int
+ipv6str_to_bytes(const char *str, char *ip)
+{
+ char block[5];
+ int res;
+ char *pos;
+ uint32_t cnt = 0, len;
+
+ dprintf("str : %s \n",str);
+
+ while (*str != 0) {
+ if (cnt > 15 || !isxdigit(*str)){
+ return 0;
+ }
+ if ((pos = strchr(str, ':')) != NULL) {
+ len = (int16_t) (pos - str);
+ dprintf("\t len is : %d \n",len);
+ if (len > 4)
+ return 0;
+ strncpy(block, str, len);
+ block[len] = 0;
+ dprintf("\t str : %s \n",str);
+ dprintf("\t block : %s \n",block);
+ str += len;
+ } else {
+ strncpy(block, str, 4);
+ block[4] = 0;
+ dprintf("\t str : %s \n",str);
+ dprintf("\t block : %s \n",block);
+ str += strlen(block);
+ }
+ res = strtol(block, NULL, 16);
+ dprintf("\t res : %x \n",res);
+ if ((res > 0xFFFF) || (res < 0))
+ return 0;
+ ip[cnt++] = (res & 0xFF00) >> 8;
+ ip[cnt++] = (res & 0x00FF);
+ if (*str == ':'){
+ str++;
+ }
+ }
+
+ dprintf("cnt : %d\n",cnt);
+ return cnt;
+}
+
+int str_to_ipv6(const char *str, uint8_t *ip)
+{
+ int i, k;
+ uint16_t len;
+ char *ptr;
+ char tmp[30], buf[16];
+
+ memset(ip,0,16);
+
+ if(!check_colons(str))
+ return 0;
+
+ if ((ptr = strstr(str, "::")) != NULL) {
+ /* Handle the ::1 IPv6 loopback */
+ if(!strcmp(str,"::1")) {
+ ip[15] = 1;
+ return 16;
+ }
+ len = (ptr-str);
+ dprintf(" len : %d \n",len);
+ if (len >= sizeof(tmp))
+ return 0;
+ strncpy(tmp, str, len);
+ tmp[len] = 0;
+ ptr += 2;
+
+ i = ipv6str_to_bytes(ptr, buf);
+ if(i == 0)
+ return i;
+
+ #if defined(ARGS_DEBUG)
+ int j;
+ dprintf("=========== bottom part i : %d \n",i);
+ for(j=0; j<i; j++)
+ dprintf("%02x \t",buf[j]);
+ #endif
+
+ /* Copy the bottom part i.e bytes following "::" */
+ memcpy(ip+(16-i), buf, i);
+
+ k = ipv6str_to_bytes(tmp, buf);
+ if(k == 0)
+ return k;
+
+ #if defined(ARGS_DEBUG)
+ dprintf("=========== top part k : %d \n",k);
+ for(j=0; j<k; j++)
+ printf("%02x \t",buf[j]);
+ #endif
+
+ /* Copy the top part i.e bytes before "::" */
+ memcpy(ip, buf, k);
+ #if defined(ARGS_DEBUG)
+ dprintf("\n");
+ for(j=0; j<16; j++)
+ dprintf("%02x \t",ip[j]);
+ #endif
+
+ } else {
+ i = ipv6str_to_bytes(str, (char *)ip);
+ }
+ return i;
+}
+
+void ipv6_to_str(const uint8_t *ip, char *str)
+{
+ int i, len;
+ uint8_t byte_even, byte_odd;
+ char *consec_zero, *strptr;
+
+ *str = 0;
+ for (i = 0; i < 16; i+=2) {
+ byte_even = ip[i];
+ byte_odd = ip[i+1];
+ if (byte_even)
+ sprintf(str, "%s%x%02x", str, byte_even, byte_odd);
+ else if (byte_odd)
+ sprintf(str, "%s%x", str, byte_odd);
+ else
+ strcat(str, "0");
+ if (i != 14)
+ strcat(str, ":");
+ }
+ strptr = str;
+ do {
+ consec_zero = strstr(strptr, "0:0:");
+ if (consec_zero) {
+ len = consec_zero - strptr;
+ if (!len)
+ break;
+ else if (strptr[len-1] == ':')
+ break;
+ else
+ strptr = consec_zero + 2;
+ }
+ } while (consec_zero);
+ if (consec_zero) {
+ len = consec_zero - str;
+ str[len] = 0;
+ if (len)
+ strcat(str, ":");
+ else
+ strcat(str, "::");
+ strptr = consec_zero + 4;
+ while (*strptr) {
+ if (!strncmp(strptr, "0:", 2))
+ strptr += 2;
+ else
+ break;
+ }
+ strcat(str, strptr);
+ if (!strcmp(str, "::0"))
+ strcpy(str, "::");
+ }
+}
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