ip.h File Reference

#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>

Go to the source code of this file.

Data Structures
struct	addrinfo

Macros
#define	MAX_IP_ADDR_LEN   1024

Functions
void	get_local_ip_address (char *ip_addr)
	Get the local IP address of the machine (e.g.
void	get_remote_ip_address (char *ip_addr)
	Get the remote IP address of the machine (e.g.
int	lookup_address (const char *lookup_addr, char *ip_addr)
	Perform lookup of given IP address by the domain address (e.g.
int	is_in_private_network (const char *ip_addr)
	Check if the IP address is in the private prefix (e.g.
int	is_numeric_address (const char *ip_addr)
	Check if the IP address is a numeric address (e.g.
int	is_valid_domain_address (const char *domain_addr)
	Check if the IP address is a valid domain address (e.g.
int	getaddrinfo (const char *restrict node, const char *restrict service, const struct addrinfo *restrict hints, struct addrinfo **restrict res)
void	freeaddrinfo (struct addrinfo *res)
const char *	gai_strerror (int errcode)

Macro Definition Documentation

MAX_IP_ADDR_LEN

#define MAX_IP_ADDR_LEN   1024

Definition at line 8 of file ip.h.

Function Documentation

freeaddrinfo()

void freeaddrinfo

(

struct addrinfo *

res

)

Referenced by lookup_address().

gai_strerror()

const char * gai_strerror

(

int

errcode

)

Referenced by lookup_address().

get_local_ip_address()

void get_local_ip_address

(

char *

ip_addr

)

Get the local IP address of the machine (e.g.

192.168.1.10).

Parameters

ip_addr

The buffer to store the IP address.

Definition at line 11 of file ip.c.

{
    FILE* file = popen("hostname -I", "r");
    if (file == NULL)
    {
        strcpy(ip_addr, " ");
        return;
    }
    char buffer[BUFFER_SIZE];
    if (fgets(buffer, sizeof(buffer), file) == NULL)
    {
        strcpy(ip_addr, " ");
        pclose(file);
        return;
    }
    pclose(file);
    char* newline = strchr(buffer, '\n');
    if (newline != NULL)
        *newline = '\0';
    strcpy(ip_addr, buffer);
}

References BUFFER_SIZE, pclose(), and popen().

Referenced by cli_whoami().

get_remote_ip_address()

void get_remote_ip_address

(

char *

ip_addr

)

Get the remote IP address of the machine (e.g.

1.1.1.1).

Parameters

ip_addr

The buffer to store the IP address.

Definition at line 33 of file ip.c.

{
    FILE* file = popen("curl -s ifconfig.me", "r");
    if (file == NULL)
    {
        strcpy(ip_addr, " ");
        return;
    }
    char buffer[BUFFER_SIZE];
    if (fgets(buffer, sizeof(buffer), file) == NULL)
    {
        strcpy(ip_addr, " ");
        pclose(file);
        return;
    }
    pclose(file);
    char* newline = strchr(buffer, '\n');
    if (newline != NULL)
        *newline = '\0';
    strcpy(ip_addr, buffer);
}

References BUFFER_SIZE, pclose(), and popen().

Referenced by cli_get_ip(), and cli_whoami().

getaddrinfo()

int getaddrinfo	(	const char *restrict	node,
		const char *restrict	service,
		const struct addrinfo *restrict	hints,
		struct addrinfo **restrict	res
	)

Referenced by lookup_address().

is_in_private_network()

int is_in_private_network

(

const char *

ip_addr

)

Check if the IP address is in the private prefix (e.g.

192.168.1.10 is, 1.1.1.1 is not).

Parameters

ip_addr

The IP address to check.

Returns

1 if the IP address is in the private network, 0 otherwise.

Definition at line 98 of file ip.c.

{
    if (!is_numeric_address(ip_addr))
    {
        char ip[BUFFER_SIZE];
        log_message(LOG_WARN, BITLAB_LOG, __FILE__, "IP address is not numeric, performing lookup of %s whether it is in private prefix", ip_addr);
        lookup_address(ip_addr, ip);
        return is_in_private_network(ip);
    }
    unsigned int b1, b2, b3, b4;
    if (ip_addr == NULL)
        return 0;
    if (sscanf(ip_addr, "%u.%u.%u.%u", &b1, &b2, &b3, &b4) != 4)
        return 0;
    if ((b1 == 192 && b2 == 168) ||
        (b1 == 10) ||
        (b1 == 172 && b2 >= 16 && b2 <= 31))
        return 1;
    return 0;
}

References BITLAB_LOG, BUFFER_SIZE, is_in_private_network(), is_numeric_address(), log_message(), LOG_WARN, and lookup_address().

Referenced by is_in_private_network(), and send_getaddr_and_wait().

is_numeric_address()

int is_numeric_address

(

const char *

ip_addr

)

Check if the IP address is a numeric address (e.g.

1.1.1.1 is, example.com is not).

Parameters

ip_addr

The IP address to check.

Returns

1 if the IP address is a numeric address, 0 otherwise.

Definition at line 119 of file ip.c.

{
    if (ip_addr == NULL)
        return 0;
    int dots = 0;
    for (size_t i = 0; i < strlen(ip_addr); ++i)
    {
        if (ip_addr[i] == '.')
            dots++;
        else if (ip_addr[i] < '0' || ip_addr[i] > '9')
            return 0;
        if (dots > 3)
            return 0;
    }
    return 1;
}

Referenced by cli_connect(), is_in_private_network(), and is_valid_domain_address().

is_valid_domain_address()

int is_valid_domain_address

(

const char *

domain_addr

)

Check if the IP address is a valid domain address (e.g.

example.com is, example or 1.1.1.1 is not).

Parameters

domain_addr

The domain address to check.

Returns

1 if the IP address is a valid domain address, 0 otherwise.

Definition at line 136 of file ip.c.

{
    if (domain_addr == NULL)
        return 0;
    if (is_numeric_address(domain_addr))
        return 0;
    if (strstr(domain_addr, ".") == NULL)
        return 0;
    char ip[BUFFER_SIZE];
    lookup_address(domain_addr, ip);
    if (strlen(ip) == 0)
        log_message(LOG_WARN, BITLAB_LOG, __FILE__, "Although %s is a valid domain, it does not resolve", domain_addr);
    return 1;
}

References BITLAB_LOG, BUFFER_SIZE, is_numeric_address(), log_message(), LOG_WARN, and lookup_address().

Referenced by cli_get_ip().

lookup_address()

int lookup_address	(	const char *	lookup_addr,
		char *	ip_addr
	)

Perform lookup of given IP address by the domain address (e.g.

google.com).

Parameters

lookup_addr	The current address to lookup.
ip_addr	The buffer to store the IP address.

Returns

0 if successful, otherwise -1 or 1.

Definition at line 55 of file ip.c.

{
    struct addrinfo hints, * res, * p;
    int status;
    char ipstr[INET6_ADDRSTRLEN];
 
    memset(ip_addr, 0, MAX_IP_ADDR_LEN);
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
 
    if ((status = getaddrinfo(lookup_addr, NULL, &hints, &res)) != 0)
    {
        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(status));
        ip_addr[0] = '\0';
        return -1;
    }
 
    for (p = res; p != NULL; p = p->ai_next)
    {
        void* addr = NULL;
        if (p->ai_family == AF_INET)
        {
            struct sockaddr_in* ipv4 = (struct sockaddr_in*)p->ai_addr;
            addr = &(ipv4->sin_addr);
            if (addr != NULL)
            {
                if (strcmp(inet_ntoa(ipv4->sin_addr), "0.0.0.0") == 0)
                    log_message(LOG_WARN, BITLAB_LOG, __FILE__, "Failed to resolve %s. Appending 0.0.0.0", lookup_addr);
                inet_ntop(p->ai_family, addr, ipstr, sizeof(ipstr));
                strcat(ip_addr, ipstr);
                strcat(ip_addr, " ");
            }
        }
    }
 
    if (strlen(ip_addr) > 0)
        ip_addr[strlen(ip_addr) - 1] = '\0';
 
    freeaddrinfo(res);
    return 0;
}

References addrinfo::ai_addr, addrinfo::ai_family, addrinfo::ai_next, addrinfo::ai_socktype, BITLAB_LOG, freeaddrinfo(), gai_strerror(), getaddrinfo(), log_message(), LOG_WARN, and MAX_IP_ADDR_LEN.

Referenced by cli_get_ip(), handle_peer_discovery(), is_in_private_network(), and is_valid_domain_address().