Function anetResolve

app/redis-6.2.6/src/anet.c:233–258

Resolve the hostname "host" and set the string representation of the * IP address into the buffer pointed by "ipbuf". * * If flags is set to ANET_IP_ONLY the function only resolves hostnames * that are actually already IPv4 or IPv6 addresses. This turns the function * into a validating / normalizing function. */

 * that are actually already IPv4 or IPv6 addresses. This turns the function
 * into a validating / normalizing function. */
int anetResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len,
                       int flags)
{
    struct addrinfo hints, *info;
    int rv;

    memset(&hints,0,sizeof(hints));
    if (flags & ANET_IP_ONLY) hints.ai_flags = AI_NUMERICHOST;
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;  /* specify socktype to avoid dups */

    if ((rv = getaddrinfo(host, NULL, &hints, &info)) != 0) {
        anetSetError(err, "%s", gai_strerror(rv));
        return ANET_ERR;
    }
    if (info->ai_family == AF_INET) {
        struct sockaddr_in *sa = (struct sockaddr_in *)info->ai_addr;
        inet_ntop(AF_INET, &(sa->sin_addr), ipbuf, ipbuf_len);
    } else {
        struct sockaddr_in6 *sa = (struct sockaddr_in6 *)info->ai_addr;
        inet_ntop(AF_INET6, &(sa->sin6_addr), ipbuf, ipbuf_len);
    }

    freeaddrinfo(info);
    return ANET_OK;
}

static int anetSetReuseAddr(char *err, int fd) {
    int yes = 1;