Hello,
Thanks for this, it's indeed useful and well-contained for a
contribution.
Samuel
Gianluca Cannata, le mer. 21 janv. 2026 09:31:37 +0100, a ecrit:
> Index: httpfs/http.c
> ===================================================================
> --- httpfs.orig/http.c
> +++ httpfs/http.c
> @@ -34,14 +34,59 @@
> #include <hurd/hurd_types.h>
> #include <hurd/netfs.h>
>
> -/* do a DNS lookup for NAME and store result in *ENT */
> -error_t lookup_host (char *url, struct hostent **ent)
> +/* do a DNS lookup for HOST and store result in *DEST */
> +error_t lookup_host (const char *host, struct sockaddr_storage *dest,
> socklen_t *dest_len)
> {
> - if ( (*ent = gethostbyname(url)) == NULL )
> - {
> - fprintf(stderr,"wrong host name\n");
> + struct addrinfo hints;
> + struct addrinfo *res;
> + int s;
> +
> + /* Buffer that holds a clean host, that is a host without square
> brackets in case of a IPv6 address */
> + char clean_host[256];
Rather than hard-coding 256, you can use strlen(host)-1. Then you won't
have an ENAMETOOLONG error.
> + const char *host_ptr = host;
You don't need a separate host_ptr variable. When using clean_host, you
can as well just do host = clean_host.
> + if (!host || !dest || !dest_len)
> return EINVAL;
> +
> + /* IPv6 syntax transformation: e.g. [2001:db8::1] -> 2001:db8::1
> + * because getaddrinfo does not accept square brackets, but URLs do.
> + */
> + if (host[0] == '[') {
> + const char *end = strchr (host, ']');
If you have an opening bracket, the closing bracket should be the last
character anyway, so you can as well directly check for ']' at the end,
and return EINVAL otherwise.
> + if (end) {
> + size_t host_len = end - host - 1;
> + if (host_len >= sizeof (clean_host)) return
> ENAMETOOLONG;
> +
> + strncpy (clean_host, host + 1, host_len);
Better use memcpy.
> + clean_host[host_len] = '\0';
> + host_ptr = clean_host;
> + }
> }
> +
> + memset (&hints, 0, sizeof (struct addrinfo));
better use sizeof(hints), which we then know for sure is correct.
> + hints.ai_family = AF_UNSPEC; /* IPv4 and IPv6 */
> + hints.ai_socktype = SOCK_STREAM; /* TCP */
> + /* AI_ADDRCONFIG: Asks for AAAA record only if the host has IPv6
> connectivity.
> + * AI_V4MAPPED: Maps IPv4 to IPv6 if necessary. */
> + hints.ai_flags = AI_ADDRCONFIG | AI_V4MAPPED;
> +
> + /* DNS lookup */
> + s = getaddrinfo (host_ptr, NULL, &hints, &res);
> + if (s != 0) {
> + if (debug_flag)
> + fprintf (stderr, "DNS lookup failed for %s: %s\n",
> host_ptr, gai_strerror (s));
> +
> + return ENOENT;
> + }
> +
> + /* TODO: Shall we copy only the first result or iterate through
> possible multiple results */
Ideally we'd try to connect to each result until one succeeds. But that
will do for now.
> + if (res != NULL) {
> + memcpy (dest, res->ai_addr, res->ai_addrlen);
> + *dest_len = res->ai_addrlen;
> + dest->ss_family = res->ai_family;
res->ai_addr.sa_family will already have filled dest->ss_family, no need
to fill it again.
> + }
> +
> + freeaddrinfo (res);
> return 0;
> }
>
> @@ -52,8 +97,8 @@ error_t open_connection(struct netnode *
> * head. *HEAD_LEN indicates the header length, for pruning upto that
> */
>
> error_t err;
> - struct hostent *hptr;
> - struct sockaddr_in dest;
> + struct sockaddr_storage server_addr;
> + socklen_t addr_len;
> ssize_t written;
> size_t towrite;
> char buffer[4096];
> @@ -63,49 +108,39 @@ error_t open_connection(struct netnode *
> char delimiters0[] = " ";
> char delimiters1[] = "\n";
>
> - bzero(&dest,sizeof(dest));
> - dest.sin_family = AF_INET;
> - dest.sin_port = htons (port);
> -
> - if ( !strcmp(ip_addr,"0.0.0.0") )
> - {
> - /* connection is not through a proxy server
> - * find IP addr. of remote server */
> - err = lookup_host (node->url, &hptr);
> - if (err)
> - {
> - fprintf(stderr,"Could not find IP addr
> %s\n",node->url);
> - return err;
> - }
> - dest.sin_addr = *(struct in_addr *)hptr->h_addr;
> - }
> - else
> - {
> - /* connection is through the proxy server
> - * need not find IP of remote server
> - * find IP of the proxy server */
> - if ( inet_aton(ip_addr,&dest.sin_addr) == 0 )
> - {
> - fprintf(stderr,"Invalid IP for proxy\n");
> - return -1;
> - }
> + /* 1. Target selection.
> + * If ip_addr (proxy global variable) is set, we use it.
> + * Otherwise we use the node URL.
> + */
> + const char *target_host = (strcmp (ip_addr, "0.0.0.0") != 0) ?
> ip_addr : node->url;
> +
> + /* 2. Agnostic resolution (IPv4/IPv6) */
> + if ((err = lookup_host (target_host, &server_addr, &addr_len)) != 0) {
> + fprintf (stderr, "Cannot resolve host: %s\n", target_host);
> + return err;
> + }
> +
> + /* 3. Set of the port. */
> + if (server_addr.ss_family == AF_INET) {
> + ((struct sockaddr_in *)&server_addr)->sin_port = htons (port);
> + } else if (server_addr.ss_family == AF_INET6) {
> + ((struct sockaddr_in6 *)&server_addr)->sin6_port = htons
> (port);
> }
>
> if (debug_flag)
> - fprintf (stderr, "trying to open %s:%d/%s\n", node->url,
> - port, node->conn_req);
> + fprintf (stderr, "Connecting to %s via %s:%d\n", node->url,
> target_host, port);
>
> - *fd = socket (AF_INET, SOCK_STREAM, 0);
> + /* 4. First connection: HEAD request */
> + *fd = socket (server_addr.ss_family, SOCK_STREAM, 0);
Ideally, you'd make lookup_host also take more parameters, to be filled
by res->ai_socktype and res->ai_protocol, instead of hardcoding
SOCK_STREAM and 0.
> if (*fd == -1)
> {
> - fprintf(stderr,"Socket creation error\n");
> + perror ("Socket creation error for HEAD request");
> return errno;
> }
>
> - err = connect (*fd, (struct sockaddr *)&dest, sizeof (dest));
> - if (err == -1)
> - {
> - fprintf(stderr,"Cannot connect to remote host\n");
> + if (connect (*fd, (struct sockaddr *)&server_addr, addr_len) == -1) {
> + perror ("Connection to remote host failed");
> + close (*fd);
> return errno;
> }
>
> @@ -142,21 +177,20 @@ error_t open_connection(struct netnode *
>
> close(*fd);
>
> + /* 5. Second connection: GET request */
> /* Send the GET request for the url */
> - *fd = socket (AF_INET, SOCK_STREAM, 0);
> + *fd = socket (server_addr.ss_family, SOCK_STREAM, 0);
Ditto
> if (*fd == -1)
> {
> - fprintf(stderr,"Socket creation error\n");
> + perror ("Socket creation error for GET request");
> return errno;
> }
>
> - err = connect (*fd, (struct sockaddr *)&dest, sizeof (dest));
> - if (err == -1)
> - {
> - fprintf(stderr,"Cannot connect to remote host\n");
> + if (connect (*fd, (struct sockaddr *)&server_addr, addr_len) == -1) {
> + perror ("Connection to remote host failed");
> + close (*fd);
> return errno;
> }
> -
> towrite = strlen (node->comm_buf);
>
> /* guard against EINTR failures */
> Index: httpfs/httpfs.h
> ===================================================================
> --- httpfs.orig/httpfs.h
> +++ httpfs/httpfs.h
> @@ -119,8 +119,8 @@ error_t parse(struct netnode *node);
> * string */
> void extract(char *string,char *parent);
>
> -/* do a DNS lookup for NAME and store result in *ENT */
> -error_t lookup_host (char *url, struct hostent **ent);
> +/* do a DNS lookup for HOST and store result in *DEST */
> +error_t lookup_host (const char *url, struct sockaddr_storage *dest,
> socklen_t *dest_len);
>
> /* store the remote socket in *FD and establish the connection and send the
> * http GET request */
