/*
*##############################################################################################
*
* ICMPv6 Neighbor Advertisement Unsolicited Message C program
*
*##############################################################################################
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> /* close() */
#include <string.h> /* strcpy, memset(), and memcpy() */
#include <netdb.h> /* struct addrinfo */
#include <sys/types.h> /* needed for socket(), uint8_t, uint16_t */
#include <sys/socket.h> /* needed for socket() */
#include <netinet/in.h> /* IPPROTO_ICMPV6, INET6_ADDRSTRLEN */
#include <netinet/ip.h> /* IP_MAXPACKET (which is 65535) */
#include <netinet/ip6.h> /* struct ip6_hdr */
#include <netinet/icmp6.h> /* struct icmp6_hdr and ICMP6_ECHO_REQUEST */
#include <arpa/inet.h> /* inet_pton() and inet_ntop() */
#include <sys/ioctl.h> /* macro ioctl is defined */
#include <bits/ioctls.h> /* defines values for argument "request" of ioctl. */
#include <net/if.h> /* struct ifreq */
#include <linux/if_ether.h> /* ETH_P_IP = 0x0800, ETH_P_IPV6 = 0x86DD */
#include <linux/if_packet.h> /* struct sockaddr_ll (see man 7 packet) */
#include <net/ethernet.h>
#include <errno.h> /* errno, perror() */
/* Various Header Lengths */
#define ETH_HDRLEN 14 /* Ethernet header length */
#define IPV6_HDRLEN 40 /* IPv6 header length */
#define ICMPV6_HDRLEN 24 /* ICMPv6 header length for neighbor advertisement unsolicited */
#define ICMPV6_OPTION_HDLEN 8 /* ICMPv6 option header length for neighbor advertisement unsolicited */
/*
* Function prototypes
*/
uint16_t checksum(uint16_t *, int);
uint16_t icmp6_checksum(struct ip6_hdr,
struct nd_neighbor_advert,
uint8_t *,
int);
char *allocate_strmem(int);
uint8_t *allocate_ustrmem(int);
/*
*#####################################################################################
* MAIN FUNCTION STARTS HERE
*#####################################################################################
*/
int main (int argc, char **argv)
{
int i, status, frame_length, sd, bytes;
char *interface = NULL,
*target = NULL,
*src_ip = NULL,
*dst_ip = NULL;
uint8_t *src_mac = NULL,
*ether_frame = NULL;
uint8_t *multicast_dest_mac_in_bytes = NULL;
struct addrinfo hints, *res;
struct sockaddr_in6 *ipv6;
struct sockaddr_in6 icmpv6_target_ipv6_address;
struct sockaddr_ll device;
struct ifreq ifr;
void *tmp = NULL;
char multicast_dest_mac_in_str[24] = {0};
char *ipv6_header_dest_ip_addr = NULL;
/*
* Structures for ipv6 , icmpv6 Neighbor Advertisement and
* icmpv6 options header.
*/
struct ip6_hdr ipv6_hdr;
struct icmp6_hdr icmphdr;
struct nd_neighbor_advert na;
unsigned char icmpv6_option1[ICMPV6_OPTION_HDLEN]={0};
/*
* argv[1]: Outgoing interface
* argv[2]: source ipv6 address
* argv[3]: destination ipv6 address
*/
if (argc != 4) {
printf("Invalid input : %d\n", argc);
printf("Help section\n"
"=====================================\n"
"Enter 3 arguments:\n"
"1. Outgoing Interface Name\n"
"2. Source IPV6 Address\n"
"3. ICMPV6 Target IP Address\n"
);
printf("Input Arguments: %s %s %s\n",
argv[1], argv[2], argv[3]);
return -1;
}
/*
* Allocate memory for various arrays.
*/
src_mac = allocate_ustrmem(6);
multicast_dest_mac_in_bytes = allocate_ustrmem(6);
ether_frame = allocate_ustrmem(IP_MAXPACKET);
interface = allocate_strmem(40);
target = allocate_strmem(INET6_ADDRSTRLEN);
src_ip = allocate_strmem(INET6_ADDRSTRLEN);
dst_ip = allocate_strmem(INET6_ADDRSTRLEN);
ipv6_header_dest_ip_addr = allocate_strmem(INET6_ADDRSTRLEN);
/*
*****************************************************************************
* INTERFACE, SOURCE IPV6 ADDRESS, DESTINATION IPV6 ADDRESS,
* DESTINATION MAC ADDRESS AND SOURCE MAC ADDRESS
*****************************************************************************
* */
/* Interface to send packet through. */
strcpy(interface, argv[1]);
/* Source IPv6 address: you need to fill this out */
strcpy(src_ip, argv[2]);
/*
* Destination IPv6 address either:
* 1) unicast address of node which sent solicitation, or if the
* solicitation came from the unspecified address (::), use the
* 2) IPv6 "all nodes" link-local multicast address (ff02::1).
* You need to fill this out.
* ipv6 address to be programmed in IPV6 header--> all nodes link local multicast address
*/
strcpy(ipv6_header_dest_ip_addr, "ff02::1");
/* ICMPV6 target ip address.. is the link local ip address of the router */
strcpy (target, argv[3]);
/* ethernet header ipv6 destination multicast MAC */
strcpy(multicast_dest_mac_in_str, "33:33:00:00:00:01");
sscanf(multicast_dest_mac_in_str, "%x:%x:%x:%x:%x:%x",
(unsigned int *)&multicast_dest_mac_in_bytes[0],
(unsigned int *)&multicast_dest_mac_in_bytes[1],
(unsigned int *)&multicast_dest_mac_in_bytes[2],
(unsigned int *)&multicast_dest_mac_in_bytes[3],
(unsigned int *)&multicast_dest_mac_in_bytes[4],
(unsigned int *)&multicast_dest_mac_in_bytes[5]);
/******************************************************************************/
/* Submit request for a socket descriptor to look up interface. */
if ((sd = socket(PF_PACKET, SOCK_RAW, htons (ETH_P_ALL))) < 0) {
perror ("socket() failed to get socket descriptor for using ioctl() ");
exit (EXIT_FAILURE);
}
/* Use ioctl() to look up interface name and get its MAC address. */
memset(&ifr, 0, sizeof(ifr));
snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", interface);
if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0) {
perror("ioctl() failed to get source MAC address ");
return (EXIT_FAILURE);
}
close (sd);
/* Copy source MAC address. */
memcpy(src_mac, ifr.ifr_hwaddr.sa_data, 6 * sizeof (uint8_t));
/*
* Print Source MAC address of source interface from which the
* packet will go out.
*/
printf("MAC address for interface %s is ", interface);
for (i=0; i<5; i++) {
printf("%02x:", src_mac[i]);
}
printf("%02x\n", src_mac[5]);
/*
* Find interface index from interface name and store index in
* struct sockaddr_ll device,
* which will be used as an argument of sendto().
*/
memset(&device, 0, sizeof (device));
if ((device.sll_ifindex = if_nametoindex (interface)) == 0) {
perror ("if_nametoindex() failed to obtain interface index ");
exit (EXIT_FAILURE);
}
printf ("Index for interface %s is %i\n", interface, device.sll_ifindex);
/*
* THIS IS ONLY NEEDED WHEN TARGET IS URL AND NOT IP ADDRESS. IN THAT CASE,
* IP ADDRESS OF THE DESTINATION IS DERIVED USING 'getaddrinfo() API
*/
/* Fill out hints for getaddrinfo(). */
memset (&hints, 0, sizeof (hints));
hints.ai_family = AF_INET6;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = hints.ai_flags | AI_CANONNAME;
/* Resolve target using getaddrinfo(). */
if ((status = getaddrinfo (src_ip, NULL, &hints, &res)) != 0) {
fprintf (stderr, "getaddrinfo() failed: %s\n", gai_strerror (status));
exit (EXIT_FAILURE);
}
memset(&icmpv6_target_ipv6_address, '\0', sizeof(icmpv6_target_ipv6_address));
memcpy(&icmpv6_target_ipv6_address, res->ai_addr, res->ai_addrlen);
ipv6 = (struct sockaddr_in6 *)res->ai_addr;
tmp = &(ipv6->sin6_addr);
if (inet_ntop (AF_INET6, tmp, dst_ip, INET6_ADDRSTRLEN) == NULL) {
status = errno;
fprintf (stderr, "inet_ntop() failed.\nError message: %s", strerror (status));
exit (EXIT_FAILURE);
}
freeaddrinfo (res);
printf("Destination IPV6 address derived from target: %s\n", dst_ip);
/*
*#################################################################################
* THE ACTUAL ICMPV6 PACKET HEADER FORMATION BEGINS FROM THIS PLACE
*#################################################################################
*/
/* Fill out sockaddr_ll. */
device.sll_family = AF_PACKET;
memcpy (device.sll_addr, src_mac, 6 * sizeof (uint8_t));
device.sll_halen = 6;
/*
* Frame 10635: 86 bytes on wire (688 bits), 86 bytes captured (688 bits) on interface 0
Interface id: 0 (wlp4s0)
Interface name: wlp4s0
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ L2 Ethernet header
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Ethernet II, Src: IntelCor_19:8e:f8 (7c:b0:c2:19:8e:f8), Dst: IPv6mcast_01 (33:33:00:00:00:01)
Destination: IPv6mcast_01 (33:33:00:00:00:01)
Address: IPv6mcast_01 (33:33:00:00:00:01)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
Source: IntelCor_19:8e:f8 (7c:b0:c2:19:8e:f8)
Address: IntelCor_19:8e:f8 (7c:b0:c2:19:8e:f8)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IPv6 (0x86dd)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ L3 IPV6 header
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Internet Protocol Version 6, Src: fe80::ad6:3956:56b0:97d7, Dst: ff02::1
0110 .... = Version: 6
.... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
.... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
.... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
.... .... .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000
Payload Length: 32
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ ICMPV6 header (24 bytes)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Next Header: ICMPv6 (58)
Hop Limit: 255
Source: fe80::ad6:3956:56b0:97d7
Destination: ff02::1
Internet Control Message Protocol v6
Type: Neighbor Advertisement (136)
Code: 0
Checksum: 0xa672 [correct]
[Checksum Status: Good]
Flags: 0xa0000000, Router, Override
1... .... .... .... .... .... .... .... = Router: Set
.0.. .... .... .... .... .... .... .... = Solicited: Not set
..1. .... .... .... .... .... .... .... = Override: Set
...0 0000 0000 0000 0000 0000 0000 0000 = Reserved: 0
Target Address: fe80::ad6:3956:56b0:97d7
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ ICMPV6 option header (8 bytes)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
ICMPv6 Option (Target link-layer address : 7c:b0:c2:19:8e:f8)
Type: Target link-layer address (2)
Length: 1 (8 bytes)
Link-layer address: IntelCor_19:8e:f8 (7c:b0:c2:19:8e:f8)
*/
/* IPV6 HEADER */
/*
* 0 and 1) IPv6 version (4 bits), Traffic class (8 bits), Flow label (20 bits) = [32 bits or 4 bytes]
* 2) Payload length = ICMP header(24 bytes) + ICMP option header(8 bytes) = [32 bytes]
* 3) Next header (8 bits): 58 for ICMP = [1 byte]
* 4) Hop limit (8 bits): default to maximum value = [1 byte]
* 5) Source IPv6 address (128 bits) = [16 bytes]
* 6) Destination IPv6 address (128 bits) = [16 bytes]
*/
ipv6_hdr.ip6_flow = htonl ((6 << 28) | (0 << 20) | 0);
ipv6_hdr.ip6_plen = htons(ICMPV6_HDRLEN + ICMPV6_OPTION_HDLEN);
ipv6_hdr.ip6_nxt = IPPROTO_ICMPV6;
ipv6_hdr.ip6_hops = 255;
if ((status = inet_pton(AF_INET6, src_ip, &(ipv6_hdr.ip6_src))) != 1) {
fprintf (stderr, "inet_pton() failed.\nError message: %s", strerror (status));
exit (EXIT_FAILURE);
}
if ((status = inet_pton(AF_INET6, ipv6_header_dest_ip_addr, &(ipv6_hdr.ip6_dst))) != 1) {
fprintf (stderr, "inet_pton() failed.\nError message: %s", strerror (status));
exit (EXIT_FAILURE);
}
/* IPMPV6 HEADER */
/* Populate icmp6_hdr portion of neighbor advertisement struct. */
memset(&na, 0, sizeof(na));
na.nd_na_hdr.icmp6_type = ND_NEIGHBOR_ADVERT; /* 136 (RFC 4861) */
na.nd_na_hdr.icmp6_code = 0; /* zero for neighbor solicitation (RFC 4861) */
na.nd_na_hdr.icmp6_cksum = htons(0); /* zero when calculating checksum */
/* Set R/S/O flags as: R=1, S=1, O=1. Set reserved to zero (RFC 4861) */
na.nd_na_flags_reserved = htonl((1 << 31) + (1 << 29));
na.nd_na_target = icmpv6_target_ipv6_address.sin6_addr; /* Target address (NOT MULTICAST) (as type in6_addr) */
/* ICMPV6 OPTIONS HEADER */
icmpv6_option1[0] = 2; /* Option Type - "Target link layer address" (Section 4.6 of RFC 4861) */
icmpv6_option1[1] = ICMPV6_OPTION_HDLEN/8; /* Option Length - units of 8 octets (RFC 4861) */
for (i = 0; i < 6; i++) {
icmpv6_option1[i+2] = (uint8_t) src_mac[i];
}
/*
* Ethernet frame header.
*/
#define ETH_DEST_MAC_OFFSET 0
#define ETH_DEST_MAC_LEN 6
#define ETH_SRC_MAC_OFFSET (ETH_DEST_MAC_OFFSET + ETH_DEST_MAC_LEN)
#define ETH_SRC_MAC_LEN 6
#define ETH_ETHERTYPE_LB_OFFSET (ETH_SRC_MAC_OFFSET + ETH_SRC_MAC_LEN)
#define ETH_ETHERTYPE_UB_OFFSET (ETH_ETHERTYPE_LB_OFFSET + 1)
#define ETHER_TYPE_LEN 2
/*
* Ethernet frame length =
* ethernet header (MAC + MAC + ether type) + IP6 header + ICMPV6 header + ICMPV6 OPTIONS header
*/
frame_length = ETH_DEST_MAC_LEN + ETH_SRC_MAC_LEN +
ETHER_TYPE_LEN + IPV6_HDRLEN + ICMPV6_HDRLEN + ICMPV6_OPTION_HDLEN;
/* Destination and Source MAC addresses */
memcpy (ether_frame, multicast_dest_mac_in_bytes, ETH_DEST_MAC_LEN * sizeof (uint8_t));
memcpy (ether_frame + ETH_SRC_MAC_OFFSET, src_mac, ETH_SRC_MAC_LEN * sizeof (uint8_t));
/*
* Next is ethernet type code (ETH_P_IPV6 for IPv6).
* http://www.iana.org/assignments/ethernet-numbers
*/
ether_frame[ETH_ETHERTYPE_LB_OFFSET] = ETH_P_IPV6 / 256;
ether_frame[ETH_ETHERTYPE_UB_OFFSET] = ETH_P_IPV6 % 256;
/* Next is ethernet frame data (IPv6 header + ICMPV6 header + ICMPV6 option header). */
/* IPv6 header */
memcpy (ether_frame + ETH_HDRLEN,
&ipv6_hdr, IPV6_HDRLEN * sizeof (uint8_t));
struct nd_neighbor_advert *ns_ptr = NULL;
/* ICMPV6 header */
memcpy (ether_frame + ETH_HDRLEN + IPV6_HDRLEN,
&na, ICMPV6_HDRLEN * sizeof (uint8_t));
/* ICMPV6 Option header */
memcpy(ether_frame + ETH_HDRLEN + IPV6_HDRLEN + ICMPV6_HDRLEN,
icmpv6_option1, ICMPV6_OPTION_HDLEN * sizeof (uint8_t));
/*
* In order to update the checksum, retrieve the location of checksum
* from the packet
*/
ns_ptr = (struct nd_neighbor_advert *)(ether_frame + ETH_HDRLEN + IPV6_HDRLEN);
ns_ptr->nd_na_hdr.icmp6_cksum = icmp6_checksum(ipv6_hdr, /* ip header structure */
na, /* icmpv6 NA header structure */
icmpv6_option1, /* icmpv6 options header */
ICMPV6_OPTION_HDLEN);
/*
* Create a raw socket to put the packet on the Wire.
*/
if ((sd = socket(PF_PACKET, SOCK_RAW, htons (ETH_P_ALL))) < 0) {
perror ("socket() failed ");
exit (EXIT_FAILURE);
}
/* Send ethernet frame to socket. */
if ((bytes = sendto (sd, ether_frame, frame_length,
0, (struct sockaddr *) &device,
sizeof (device))) <= 0) {
perror ("sendto() failed");
exit (EXIT_FAILURE);
}
/* Close socket descriptor. */
close (sd);
/* Free allocated memory. */
free (src_mac);
free (multicast_dest_mac_in_bytes);
free (ether_frame);
free (interface);
free (target);
free (src_ip);
free (dst_ip);
free (ipv6_header_dest_ip_addr);
return (EXIT_SUCCESS);
}
/*
* Computing the internet checksum (RFC 1071).
* Note that the internet checksum does not preclude collisions.
*/
uint16_t checksum (uint16_t *addr, int len)
{
int count = len;
register uint32_t sum = 0;
uint16_t answer = 0;
/* Sum up 2-byte values until none or only one byte left. */
printf("The are bytes from the packets for calculating the checksum:\n");
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n");
while (count > 1) {
printf("%x ", htons(*addr));
sum += *(addr++);
count -= 2;
}
printf("\n@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n");
/* Add left-over byte, if any. */
if (count > 0) {
sum += *(uint8_t *) addr;
}
/*
* Fold 32-bit sum into 16 bits; we lose information by doing this,
* increasing the chances of a collision.
* sum = (lower 16 bits) + (upper 16 bits shifted right 16 bits)
*/
while (sum >> 16) {
sum = (sum & 0xffff) + (sum >> 16);
}
printf("sum: %x\n", sum);
/* Checksum is one's compliment of sum. */
answer = ~sum;
printf("1's complement of sum is answer(Final Checksum): %x\n", htons(answer));
return (answer);
}
/*
* Build IPv6 ICMP pseudo-header and call checksum function
* (Section 8.1 of RFC 2460).
*/
uint16_t icmp6_checksum (struct ip6_hdr ipv6_hdr,
struct nd_neighbor_advert na,
uint8_t *payload,
int payloadlen)
{
char buf[IP_MAXPACKET];
char *ptr = NULL;
int chksumlen = 0;
int i;
/* ptr points to beginning of buffer buf */
ptr = &buf[0];
/* Copy source IP address into buf (128 bits) */
memcpy (ptr, &ipv6_hdr.ip6_src.s6_addr, sizeof (ipv6_hdr.ip6_src.s6_addr));
ptr += sizeof (ipv6_hdr.ip6_src);
chksumlen += sizeof (ipv6_hdr.ip6_src);
/* Copy destination IP address into buf (128 bits) */
memcpy (ptr, &ipv6_hdr.ip6_dst.s6_addr, sizeof (ipv6_hdr.ip6_dst.s6_addr));
ptr += sizeof (ipv6_hdr.ip6_dst.s6_addr);
chksumlen += sizeof (ipv6_hdr.ip6_dst.s6_addr);
/*
* Copy Upper Layer Packet length into buf (32 bits).
* Should not be greater than 65535 (i.e., 2 bytes).
*/
*ptr = 0; ptr++;
*ptr = 0; ptr++;
*ptr = (ICMPV6_HDRLEN + payloadlen) / 256;
ptr++;
*ptr = (ICMPV6_HDRLEN + payloadlen) % 256;
ptr++;
chksumlen += 4;
/* Copy zero field to buf (24 bits) */
*ptr = 0; ptr++;
*ptr = 0; ptr++;
*ptr = 0; ptr++;
chksumlen += 3;
/* Copy next header field to buf (8 bits) */
memcpy (ptr, &ipv6_hdr.ip6_nxt, sizeof (ipv6_hdr.ip6_nxt));
ptr += sizeof (ipv6_hdr.ip6_nxt);
chksumlen += sizeof (ipv6_hdr.ip6_nxt);
/* Copy ICMPv6 type to buf (8 bits) */
memcpy (ptr, &na.nd_na_hdr.icmp6_type, sizeof (na.nd_na_hdr.icmp6_type));
ptr += sizeof (na.nd_na_hdr.icmp6_type);
chksumlen += sizeof (na.nd_na_hdr.icmp6_type);
/* Copy ICMPv6 code to buf (8 bits) */
memcpy (ptr, &na.nd_na_hdr.icmp6_code, sizeof (na.nd_na_hdr.icmp6_code));
ptr += sizeof (na.nd_na_hdr.icmp6_code);
chksumlen += sizeof (na.nd_na_hdr.icmp6_code);
/* Copy ICMPv6 ID to buf (16 bits) */
memcpy (ptr, &na.nd_na_hdr.icmp6_id, sizeof (na.nd_na_hdr.icmp6_id));
ptr += sizeof (na.nd_na_hdr.icmp6_id);
chksumlen += sizeof (na.nd_na_hdr.icmp6_id);
/* Copy ICMPv6 sequence number to buff (16 bits) */
memcpy (ptr, &na.nd_na_hdr.icmp6_seq, sizeof (na.nd_na_hdr.icmp6_seq));
ptr += sizeof (na.nd_na_hdr.icmp6_seq);
chksumlen += sizeof (na.nd_na_hdr.icmp6_seq);
/* Copy ICMPv6 Neighbor Target IP6 address to buff (128 bits) */
memcpy (ptr, &na.nd_na_target, sizeof (na.nd_na_target));
ptr += sizeof (na.nd_na_target);
chksumlen += sizeof (na.nd_na_target);
/*
* Copy ICMPv6 checksum to buf (16 bits)
* Zero, since we don't know it yet.
*/
*ptr = 0; ptr++;
*ptr = 0; ptr++;
chksumlen += 2;
/* Copy ICMPv6 payload to buf */
memcpy (ptr, payload, payloadlen * sizeof (uint8_t));
ptr += payloadlen;
chksumlen += payloadlen;
/* Pad to the next 16-bit boundary */
for (i = 0; i < payloadlen%2; i++, ptr++) {
*ptr = 0;
ptr += 1;
chksumlen += 1;
}
return checksum ((uint16_t *) buf, chksumlen);
}
/* Allocate memory for an array of chars. */
char * allocate_strmem(int len)
{
void *tmp;
if (len <= 0) {
fprintf(stderr, "ERROR: Cannot allocate memory because len = %i in allocate_strmem().\n", len);
exit(EXIT_FAILURE);
}
tmp = (char *) malloc(len * sizeof(char));
if (tmp != NULL) {
memset (tmp, 0, len * sizeof(char));
return(tmp);
} else {
fprintf (stderr, "ERROR: Cannot allocate memory for array allocate_strmem().\n");
exit(EXIT_FAILURE);
}
}
/* Allocate memory for an array of unsigned chars. */
uint8_t *allocate_ustrmem(int len)
{
void *tmp;
if (len <= 0) {
fprintf(stderr, "ERROR: Cannot allocate memory because len = %i in allocate_ustrmem().\n", len);
exit(EXIT_FAILURE);
}
tmp = (uint8_t *) malloc(len * sizeof (uint8_t));
if (tmp != NULL) {
memset(tmp, 0, len * sizeof (uint8_t));
return(tmp);
} else {
fprintf(stderr, "ERROR: Cannot allocate memory for array allocate_ustrmem().\n");
exit(EXIT_FAILURE);
}
}