CODEWITHSUNDEEP
csocketsipv6getaddrinfo
Kuyss
Kuyss

Reputation: 39

How do I store an IPv6 address from getaddrinfo into a character array?

I have an addrinfo structure that I get by calling the getaddrinfo() function with the following parameters:

getaddrinfo(address, NULL, &hints, &res)

I need to store the IPv6 address in binary form and print it in hexadecimal form.

My question is, how do I store the IPv6 address in a character array of 16 elements?

Upvotes: 1

Views: 1233

Answers (2)

fluter
fluter

Reputation: 13786

If getaddrinfo call was successful, then res contains a linked list of available struct addrinfo, in which you can obtain the ipaddress with its ai_addr member. If ai_family is AF_INET6, then you can copy the ipv6 address by following:

include <netinet/in.h>
unsigned char buf[INET_ADDRSTRLEN];
struct sockaddr_in6 *in6 = (struct sockaddr_in6*)addr->ai_addr;
memcpy(buf, in6->sin6_addr.s6_addr, 16);

To dump the bytes of the address:

for (int i = 0; i < 16; i++) {
    printf("%02X", buf[i]);
    if (i < 15) putchar(':');
}

To print the ipv6 address in canonical way, use inet_ntop:

char str[64];
printf("%s\n", inet_ntop(AF_INET6, buf, str, sizeof buf));

Upvotes: 5

padfoot
padfoot

Reputation: 851

After memcpy ing the address to a buffer, you could do this for hex output.

unsigned char buf[16];
memcpy(&buf, &addr, 16);`

printf("0x");
int i;
for(i = 0; i < 16; i++)
{
      if(i && i % 2 == 0)
         printf (":");
      printf("%02x", buf[i]);
}

Upvotes: 0

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