getaddrinfo.c

来自「eCos操作系统源码」· C语言 代码 · 共 528 行 · 第 1/2 页

    return EAI_NONE;
#else
    return (numeric_node_addr(ai, node, hints, port));
#endif
}

int   
getaddrinfo(const char *nodename, const char *servname,
            const struct addrinfo *hints, struct addrinfo **res)
{
    struct addrinfo dflt_hints;
    struct protoent *proto = (struct protoent *)NULL;
    struct addrinfo *ai;
    char *protoname;
    char *endptr;
    int port = 0;
    int err;

    if (hints == (struct addrinfo *)NULL) {
        dflt_hints.ai_flags = 0;  // No special flags
        dflt_hints.ai_family = PF_UNSPEC;
        dflt_hints.ai_socktype = 0;
        dflt_hints.ai_protocol = 0;
        hints = &dflt_hints;
    }
    // Prevalidate parameters
    if ((nodename == (char *)NULL) && (servname == (char *)NULL)) {
        return EAI_NONAME;
    }
    switch (hints->ai_family) {
    case PF_UNSPEC:
    case PF_INET:
        break;
#ifdef CYGPKG_NET_INET6
    case PF_INET6:
        break;
#endif
    default:
        return EAI_FAMILY;
    }
    // Allocate the first/primary result
    *res = ai = alloc_addrinfo(NULL);
    if (ai == (struct addrinfo *)NULL) {
        return EAI_MEMORY;
    }
    // Handle request
    if (hints->ai_protocol != 0) {
        proto = getprotobynumber(hints->ai_protocol);
    }
    
    // Note: this does not handle the case where a given service can be
    // handled via multiple protocols, e.g. http/tcp & http/udp
    if (servname != (char *)NULL) {
        switch (hints->ai_socktype) {
        case 0:
        case SOCK_STREAM:
            protoname = "tcp";
            ai->ai_socktype = SOCK_STREAM;
            break;
        case SOCK_DGRAM:
            protoname = "udp";
            ai->ai_socktype = SOCK_DGRAM;
            break;
        default:
            freeaddrinfo(ai);
            return EAI_SOCKTYPE;
        }
        // See if this is just a port #
        if (((port = strtol(servname, &endptr, 0)) >= 0) &&
            (endptr > servname)) {
            ai->ai_socktype = hints->ai_socktype;
            if (hints->ai_socktype == 0) {
                // Need to have complete binding type/port
                freeaddrinfo(ai);
                return EAI_SERVICE;
            }
        } else {
            struct servent *serv = (struct servent *)NULL;
            
            serv = getservbyname(servname, protoname);
            if (serv == (struct servent *)NULL) {
                if (hints->ai_socktype == 0) {
                    protoname = "udp";
                    ai->ai_socktype = SOCK_DGRAM;    
                    serv = getservbyname(servname, protoname);
                }
            }
            if (serv == (struct servent *)NULL) {
                freeaddrinfo(ai);
                return EAI_SERVICE;
            }
            port = ntohs(serv->s_port);  
        }
        proto = getprotobyname(protoname);
        if (hints->ai_protocol && (hints->ai_protocol != proto->p_proto)) {
            freeaddrinfo(ai);
            return EAI_SOCKTYPE;
        }
        ai->ai_protocol = proto->p_proto;
    }
    
    if (nodename) {
        if (hints->ai_flags & AI_NUMERICHOST) {
            err = numeric_node_addr(ai, nodename, hints, port);
        } else {
            err = with_node_addr(ai, nodename, hints, port );
        }
    } else {
        err = no_node_addr(ai, hints, port);
    }
    
    if (err != EAI_NONE) {
        freeaddrinfo(ai);
        return err;
    }

    if ((hints->ai_flags & AI_CANONNAME) && !nodename) {
        ai->ai_canonname = malloc(strlen("localhost")+1);
        if (ai->ai_canonname) {
            strcpy(ai->ai_canonname, "localhost");
        } else {
            freeaddrinfo(ai);
            return EAI_MEMORY;
        }
    }
    
    /* The DNS code may have filled in the official address. If not
       and we have been asked for it, return an error */
    if ((hints->ai_flags & AI_CANONNAME) & !ai->ai_canonname) {
        freeaddrinfo(ai);
        return EAI_FAIL;
    }
    return EAI_NONE;  // No errors
}

// The canonname will probably point to the same memory in each
// addrinfo in the linked list. Don't free it multiple times.
void  
freeaddrinfo(struct addrinfo *ai)
{
    struct addrinfo *next = ai;
    char * last_canonname = NULL;

    while ((ai = next) != (struct addrinfo *)NULL) {
        if ((ai->ai_canonname) && 
            (ai->ai_canonname != last_canonname)) { 
            free(ai->ai_canonname);
            last_canonname = ai->ai_canonname;
        }
        if (ai->ai_addr) free(ai->ai_addr);
        next = ai->ai_next;
        free(ai);
    }
}

char 
*gai_strerror(int err)
{
    switch (err) {
    case EAI_NONE:
        return "EAI - no error";
    case EAI_AGAIN:
        return "EAI - temporary failure in name resolution";
    case EAI_BADFLAGS:
        return "EAI - invalid flags";
    case EAI_FAIL:
        return "EAI - non-recoverable failure in name resolution";
    case EAI_FAMILY:
        return "EAI - family not supported";
    case EAI_MEMORY:
        return "EAI - memory allocation failure";
    case EAI_NONAME:
        return "EAI - hostname nor servname provided, or not known";
    case EAI_SERVICE:
        return "EAI - servname not supported for socket type";
    case EAI_SOCKTYPE:
        return "EAI - socket type not supported";
    case EAI_SYSTEM:
        return "EAI - system error";
    case EAI_BADHINTS:
        return "EAI - inconsistent hints";
    case EAI_PROTOCOL:
        return "EAI - bad protocol";
    default:
        return "EAI - unknown error";
    }
}

// Set of flags implemented
#define NI_MASK (NI_NUMERICHOST|NI_NUMERICSERV|NI_NOFQDN|NI_NAMEREQD|NI_DGRAM)

int 
getnameinfo (const struct sockaddr *sa, socklen_t salen, 
             char *host, socklen_t hostlen, 
             char *serv, socklen_t servlen, 
             unsigned int flags)
{
    int port;
    char *s;
    struct servent *se;
    int error;
    int numeric = (flags & NI_NUMERICHOST);

    if ((flags & ~NI_MASK) != 0) {
        return EAI_BADFLAGS;
    }
    switch (sa->sa_family) {
    case PF_INET:
#ifdef CYGPKG_NET_INET6
    case PF_INET6:
#endif
        if (host != (char *)NULL) {
            if ( !numeric) {
                error = EAI_NONAME;
#ifdef CYGPKG_NS_DNS_BUILD
                error = -cyg_dns_getnameinfo(sa, host,hostlen);
#endif
                if ((error == EAI_NONAME) && (flags & NI_NAMEREQD)) {
                    return EAI_NONAME;
                }
                // If lookup failed, try it as numeric address
                numeric = !(error == EAI_NONE);
            }
            if (numeric) {
                s = _inet_ntop((struct sockaddr *)sa, host, hostlen);
                if (!s) {
                    return EAI_FAIL;
                }
            }
            if (!numeric && flags & NI_NOFQDN) {
                s = index(host, '.');
                if (s) {
                    *s = '\0';
                }
            }
        }
    
        if (serv != (char *)NULL) {
            port = _inet_port((struct sockaddr *)sa);
            if (!port) {
                return EAI_FAIL;
            }
            se = (struct servent *)NULL;
            if ((flags & NI_NUMERICSERV) == 0) {
                if ((flags & NI_DGRAM) == 0) {
                    se = getservbyport(htons(port), "tcp");
                }
                if (se == (struct servent *)NULL) {
                    se = getservbyport(htons(port), "udp");
                }
            }
            if (se != (struct servent *)NULL) {
                diag_snprintf(serv,servlen, "%s/%s", se->s_name, se->s_proto);
            } else {
                diag_snprintf(serv,servlen, "%d", port);
            }
        }
        break;
    default:
        return EAI_FAMILY;
    }
    return EAI_NONE;
}