143 lines
4.6 KiB
C
143 lines
4.6 KiB
C
// vim:ts=4:sw=4:expandtab
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#include <config.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <netdb.h>
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#include <string.h>
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#include <yajl/yajl_gen.h>
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#include <yajl/yajl_version.h>
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#include "i3status.h"
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static char *get_sockname(struct addrinfo *addr) {
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static char buf[INET6_ADDRSTRLEN + 1];
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struct sockaddr_storage local;
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int ret;
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int fd;
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if ((fd = socket(addr->ai_family, SOCK_DGRAM, 0)) == -1) {
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perror("socket()");
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return NULL;
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}
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/* Since the socket was created with SOCK_DGRAM, this is
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* actually not establishing a connection or generating
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* any other network traffic. Instead, as a side-effect,
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* it saves the local address with which packets would
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* be sent to the destination. */
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if (connect(fd, addr->ai_addr, addr->ai_addrlen) == -1) {
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/* We don’t display the error here because most
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* likely, there just is no IPv6 connectivity.
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* Thus, don’t spam the user’s console but just
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* try the next address. */
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(void)close(fd);
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return NULL;
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}
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socklen_t local_len = sizeof(struct sockaddr_storage);
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if (getsockname(fd, (struct sockaddr *)&local, &local_len) == -1) {
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perror("getsockname()");
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(void)close(fd);
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return NULL;
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}
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memset(buf, 0, INET6_ADDRSTRLEN + 1);
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if ((ret = getnameinfo((struct sockaddr *)&local, local_len,
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buf, sizeof(buf), NULL, 0,
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NI_NUMERICHOST)) != 0) {
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fprintf(stderr, "i3status: getnameinfo(): %s\n", gai_strerror(ret));
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(void)close(fd);
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return NULL;
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}
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(void)close(fd);
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return buf;
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}
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/*
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* Returns the IPv6 address with which you have connectivity at the moment.
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* The char * is statically allocated and mustn't be freed
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*/
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static char *get_ipv6_addr(void) {
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struct addrinfo hints;
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struct addrinfo *result, *resp;
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static struct addrinfo *cached = NULL;
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/* To save dns lookups (if they are not cached locally) and creating
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* sockets, we save the fd and keep it open. */
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if (cached != NULL)
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return get_sockname(cached);
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memset(&hints, 0, sizeof(struct addrinfo));
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hints.ai_family = AF_INET6;
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hints.ai_socktype = SOCK_DGRAM;
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/* We use the public IPv6 of the K root server here. It doesn’t matter
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* which IPv6 address we use (we don’t even send any packets), as long
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* as it’s considered global by the kernel.
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* NB: We don’t use a hostname since that would trigger a DNS lookup.
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* By using an IPv6 address, getaddrinfo() will *not* do a DNS lookup,
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* but return the address in the appropriate struct. */
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if (getaddrinfo("2001:7fd::1", "domain", &hints, &result) != 0) {
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/* We don’t display the error here because most
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* likely, there just is no connectivity.
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* Thus, don’t spam the user’s console. */
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return NULL;
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}
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for (resp = result; resp != NULL; resp = resp->ai_next) {
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char *addr_string = get_sockname(resp);
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/* If we could not get our own address and there is more than
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* one result for resolving k.root-servers.net, we cannot
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* cache. Otherwise, no matter if we got IPv6 connectivity or
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* not, we will cache the (single) result and are done. */
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if (!addr_string && result->ai_next != NULL)
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continue;
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if ((cached = malloc(sizeof(struct addrinfo))) == NULL)
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return NULL;
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memcpy(cached, resp, sizeof(struct addrinfo));
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if ((cached->ai_addr = malloc(resp->ai_addrlen)) == NULL) {
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cached = NULL;
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return NULL;
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}
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memcpy(cached->ai_addr, resp->ai_addr, resp->ai_addrlen);
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freeaddrinfo(result);
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return addr_string;
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}
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freeaddrinfo(result);
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return NULL;
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}
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void print_ipv6_info(yajl_gen json_gen, char *buffer, const char *format_up, const char *format_down) {
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char *addr_string = get_ipv6_addr();
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char *outwalk = buffer;
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if (addr_string == NULL) {
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START_COLOR("color_bad");
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outwalk += sprintf(outwalk, "%s", format_down);
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END_COLOR;
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OUTPUT_FULL_TEXT(buffer);
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return;
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}
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START_COLOR("color_good");
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placeholder_t placeholders[] = {
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{.name = "%ip", .value = addr_string}};
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const size_t num = sizeof(placeholders) / sizeof(placeholder_t);
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buffer = format_placeholders(format_up, &placeholders[0], num);
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END_COLOR;
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OUTPUT_FULL_TEXT(buffer);
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free(buffer);
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}
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