Range requests as defined in RFC7233 is required for resuming
interrupted http(s) downloads for example:
ftp -C http://foo.bar/install57.iso
With this diff, httpd parses "Range" header in the requests and
provide either 206(Partial Content) or 416(Range not Satisfiable)
responses with "Content-Range" header set appropriately. Further,
it understands multi range request and generate satisfiable payloads
with "multipart/byteranges" media type.
Suggestions/comments to improve the diff are welcome.
Note, "If-Range" isn't implemented yet.
Index: server_file.c
===================================================================
RCS file: /cvs/src/usr.sbin/httpd/server_file.c,v
retrieving revision 1.51
diff -u -p -r1.51 server_file.c
--- server_file.c 12 Feb 2015 10:05:29 -0000 1.51
+++ server_file.c 17 Apr 2015 02:22:12 -0000
@@ -36,12 +36,23 @@
#define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
#define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
+#define MAX_RANGES 4
+
+struct range {
+ off_t start;
+ off_t end;
+};
int server_file_access(struct httpd *, struct client *, char *, size_t);
int server_file_request(struct httpd *, struct client *, char *,
struct stat *);
+int server_partial_file_request(struct httpd *, struct client *, char *,
+ struct stat *, char *);
int server_file_index(struct httpd *, struct client *, struct stat *);
int server_file_method(struct client *);
+int parse_range_spec(char *, size_t, struct range *);
+struct range *parse_range(char *, size_t, int *);
+int buffer_add_range(int, struct evbuffer *, struct range *);
int
server_file_access(struct httpd *env, struct client *clt,
@@ -50,6 +61,7 @@ server_file_access(struct httpd *env, st
struct http_descriptor *desc = clt->clt_descreq;
struct server_config *srv_conf = clt->clt_srv_conf;
struct stat st;
+ struct kv *r, key;
char *newpath;
int ret;
@@ -123,7 +135,13 @@ server_file_access(struct httpd *env, st
goto fail;
}
- return (server_file_request(env, clt, path, &st));
+ key.kv_key = "Range";
+ r = kv_find(&desc->http_headers, &key);
+ if (r != NULL)
+ return (server_partial_file_request(env, clt, path, &st,
+ r->kv_value));
+ else
+ return (server_file_request(env, clt, path, &st));
fail:
switch (errno) {
@@ -262,6 +280,138 @@ server_file_request(struct httpd *env, s
}
int
+server_partial_file_request(struct httpd *env, struct client *clt, char *path,
+ struct stat *st, char *range_str)
+{
+ struct http_descriptor *resp = clt->clt_descresp;
+ struct media_type *media, multipart_media;
+ struct range *range;
+ struct evbuffer *evb = NULL;
+ size_t content_length;
+ int code = 500, fd = -1, i, nranges, ret;
+ char content_range[64];
+ const char *errstr = NULL;
+ uint32_t boundary;
+
+ if ((range = parse_range(range_str, st->st_size, &nranges)) == NULL) {
+ code = 416;
+ (void)snprintf(content_range, sizeof(content_range),
+ "bytes */%lld", st->st_size);
+ errstr = content_range;
+ goto abort;
+ }
+
+ /* Now open the file, should be readable or we have another problem */
+ if ((fd = open(path, O_RDONLY)) == -1)
+ goto abort;
+
+ media = media_find(env->sc_mediatypes, path);
+ if ((evb = evbuffer_new()) == NULL) {
+ errstr = "failed to allocate file buffer";
+ goto abort;
+ }
+
+ if (nranges == 1) {
+ (void)snprintf(content_range, sizeof(content_range),
+ "bytes %lld-%lld/%lld", range->start, range->end,
+ st->st_size);
+ if (kv_add(&resp->http_headers, "Content-Range",
+ content_range) == NULL)
+ goto abort;
+
+ content_length = range->end - range->start + 1;
+ if (buffer_add_range(fd, evb, range) == 0)
+ goto abort;
+
+ } else {
+ content_length = 0;
+ boundary = arc4random();
+ /* Generate a multipart payload of byteranges */
+ while (nranges--) {
+ if ((i = evbuffer_add_printf(evb, "\r\n--%ud\r\n",
+ boundary)) == -1)
+ goto abort;
+
+ content_length += i;
+ if ((i = evbuffer_add_printf(evb,
+ "Content-Type: %s/%s\r\n",
+ media == NULL ? "application" : media->media_type,
+ media == NULL ?
+ "octet-stream" : media->media_subtype)) == -1)
+ goto abort;
+
+ content_length += i;
+ if ((i = evbuffer_add_printf(evb,
+ "Content-Range: bytes %lld-%lld/%lld\r\n\r\n",
+ range->start, range->end, st->st_size)) == -1)
+ goto abort;
+
+ content_length += i;
+ if (buffer_add_range(fd, evb, range) == 0)
+ goto abort;
+
+ content_length += range->end - range->start + 1;
+ range++;
+ }
+
+ if ((i = evbuffer_add_printf(evb, "\r\n--%ud--\r\n",
+ boundary)) == -1)
+ goto abort;
+
+ content_length += i;
+
+ /* prepare multipart/byteranges media type */
+ (void)strlcpy(multipart_media.media_type, "multipart",
+ sizeof(multipart_media.media_type));
+ (void)snprintf(multipart_media.media_subtype,
+ sizeof(multipart_media.media_subtype),
+ "byteranges; boundary=%ud", boundary);
+ media = &multipart_media;
+ }
+
+ ret = server_response_http(clt, 206, media, content_length,
+ MINIMUM(time(NULL), st->st_mtim.tv_sec));
+ switch (ret) {
+ case -1:
+ goto fail;
+ case 0:
+ /* Connection is already finished */
+ close(fd);
+ evbuffer_free(evb);
+ evb = NULL;
+ goto done;
+ default:
+ break;
+ }
+
+ if (server_bufferevent_write_buffer(clt, evb) == -1)
+ goto fail;
+
+ evbuffer_free(evb);
+ evb = NULL;
+
+ bufferevent_enable(clt->clt_bev, EV_READ|EV_WRITE);
+ if (clt->clt_persist)
+ clt->clt_toread = TOREAD_HTTP_HEADER;
+ else
+ clt->clt_toread = TOREAD_HTTP_NONE;
+ clt->clt_done = 0;
+
+ done:
+ server_reset_http(clt);
+ return (0);
+ fail:
+ bufferevent_disable(clt->clt_bev, EV_READ|EV_WRITE);
+ bufferevent_free(clt->clt_bev);
+ clt->clt_bev = NULL;
+ abort:
+ if (errstr == NULL)
+ errstr = strerror(errno);
+ server_abort_http(clt, code, errstr);
+ return (-1);
+}
+
+int
server_file_index(struct httpd *env, struct client *clt, struct stat *st)
{
char path[PATH_MAX];
@@ -467,3 +617,112 @@ server_file_error(struct bufferevent *be
server_close(clt, "unknown event error");
return;
}
+
+struct range *
+parse_range(char *str, size_t file_sz, int *nranges)
+{
+ static struct range ranges[MAX_RANGES];
+ char *p, *q;
+ int i = 0;
+
+ /* Extract range unit */
+ if ((p = strchr(str, '=')) == NULL)
+ return (NULL);
+
+ *p++ = '\0';
+ /* Check if it's a bytes range spec */
+ if (strcmp(str, "bytes") != 0)
+ return (NULL);
+
+ while ((q = strchr(p, ',')) != NULL) {
+ *q++ = '\0';
+
+ /* Extract start and end positions */
+ if (parse_range_spec(p, file_sz, &ranges[i]) == 0)
+ continue;
+
+ i += 1;
+ if (i == MAX_RANGES)
+ return (NULL);
+
+ p = q;
+ }
+
+ if (p != NULL && parse_range_spec(p, file_sz, &ranges[i]) != 0)
+ i += 1;
+
+ *nranges = i;
+ return (i ? ranges : NULL);
+}
+
+int
+parse_range_spec(char *str, size_t size, struct range *r)
+{
+ size_t start_str_len, end_str_len;
+ char *p, *start_str, *end_str;
+ const char *errstr;
+
+ if ((p = strchr(str, '-')) == NULL)
+ return (0);
+
+ *p++ = '\0';
+ start_str = str;
+ end_str = p;
+ start_str_len = strlen(start_str);
+ end_str_len = strlen(end_str);
+
+ /* Either 'start' or 'end' is optional but not both */
+ if ((start_str_len == 0) && (end_str_len == 0))
+ return (0);
+
+ if (end_str_len) {
+ r->end = strtonum(end_str, 0, LLONG_MAX, &errstr);
+ if (errstr)
+ return (0);
+
+ if ((size_t)r->end >= size)
+ r->end = size - 1;
+ } else
+ r->end = size - 1;
+
+ if (start_str_len) {
+ r->start = strtonum(start_str, 0, LLONG_MAX, &errstr);
+ if (errstr)
+ return (0);
+
+ if ((size_t)r->start >= size)
+ return (0);
+ } else {
+ r->start = size - r->end;
+ r->end = size - 1;
+ }
+
+ if (r->end < r->start)
+ return (0);
+
+ return (1);
+}
+
+int
+buffer_add_range(int fd, struct evbuffer *evb, struct range *range)
+{
+ char buf[BUFSIZ];
+ size_t n, range_sz;
+ ssize_t nread;
+
+ if (lseek(fd, range->start, SEEK_SET) == -1)
+ return (0);
+
+ range_sz = range->end - range->start + 1;
+ while (range_sz) {
+ n = MINIMUM(range_sz, sizeof(buf));
+ if ((nread = read(fd, buf, n)) == -1)
+ return (0);
+
+ evbuffer_add(evb, buf, nread);
+ range_sz -= nread;
+ }
+
+ return (1);
+}
+
Index: server_http.c
===================================================================
RCS file: /cvs/src/usr.sbin/httpd/server_http.c,v
retrieving revision 1.77
diff -u -p -r1.77 server_http.c
--- server_http.c 9 Apr 2015 16:48:29 -0000 1.77
+++ server_http.c 17 Apr 2015 02:22:12 -0000
@@ -787,6 +787,13 @@ server_abort_http(struct client *clt, u_
extraheader = NULL;
}
break;
+ case 416:
+ if (asprintf(&extraheader,
+ "Content-Range: %s\r\n", msg) == -1) {
+ code = 500;
+ extraheader = NULL;
+ }
+ break;
default:
/*
* Do not send details of the error. Traditionally,
@@ -1177,6 +1184,11 @@ server_response_http(struct client *clt,
/* Date header is mandatory and should be added as late as possible */
if (server_http_time(time(NULL), tmbuf, sizeof(tmbuf)) <= 0 ||
kv_add(&resp->http_headers, "Date", tmbuf) == NULL)
+ return (-1);
+
+ /* Accept byte ranges */
+ if (code == 200 &&
+ kv_add(&resp->http_headers, "Accept-Ranges", "bytes") == NULL)
return (-1);
/* Write completed header */
