[core] RFC 7233 Range handling for non-streaming

RFC 7233 Range handling for all non-streaming responses,
including (non-streaming) dynamic responses

(previously Range responses handled only for static files)

2 files changed, 5 insertions, 280 deletions

diff --git a/src/http-header-glue.c b/src/http-header-glue.c
index c2982951..b8c3fb9f 100644
--- a/src/http-header-glue.c
+++ b/src/http-header-glue.c
@@ -305,267 +305,9 @@ handler_t http_response_reqbody_read_error (request_st * const r, int http_statu
 }
 
 
-static int http_response_coalesce_ranges (off_t * const ranges, int n)
-{
-    /* coalesce/combine overlapping ranges and ranges separated by a
-     * gap which is smaller than the overhead of sending multiple parts
-     * (typically around 80 bytes) ([RFC7233] 4.1 206 Partial Content)
-     * (ranges are known to be positive, so subtract 80 instead of add 80
-     *  to avoid any chance of integer overflow)
-     * (max n should be limited in caller since a malicious set of ranges has
-     *  n^2 cost for the simplistic algorithm below)
-     * (sorting the ranges and then combining would lower the cost, but the
-     *  cost should not be an issue since client should not send many ranges
-     *  and caller should restrict the max number of ranges to limit abuse)
-     * [RFC7233] 4.1 206 Partial Content recommends:
-     *   When a multipart response payload is generated, the server SHOULD send
-     *   the parts in the same order that the corresponding byte-range-spec
-     *   appeared in the received Range header field, excluding those ranges
-     *   that were deemed unsatisfiable or that were coalesced into other ranges
-     */
-    for (int i = 0; i+2 < n; i += 2) {
-        const off_t b = ranges[i];
-        const off_t e = ranges[i+1];
-        for (int j = i+2; j < n; j += 2) {
-            /* common case: ranges do not overlap */
-            if (b <= ranges[j] ? e < ranges[j]-80 : ranges[j+1] < b-80)
-                continue;
-            /* else ranges do overlap, so combine into first range */
-            ranges[i]   = b <= ranges[j]   ? b : ranges[j];
-            ranges[i+1] = e >= ranges[j+1] ? e : ranges[j+1];
-            memmove(ranges+j, ranges+j+2, (n-j-2)*sizeof(off_t));
-            /* restart outer loop from beginning */
-            n -= 2;
-            i = -2;
-            break;
-        }
-    }
-
-    return n;
-}
-
-
-static int http_response_parse_range(request_st * const r, stat_cache_entry * const sce, const char * const range) {
-	int n = 0;
-	int error;
-	off_t start, end;
-	const off_t st_size = sce->st.st_size;
-	const char *s, *minus;
-	static const char boundary[] = "fkj49sn38dcn3";
-	const buffer *content_type =
-	  http_header_response_get(r, HTTP_HEADER_CONTENT_TYPE,
-	                           CONST_STR_LEN("Content-Type"));
-	off_t ranges[16];
-
-	start = 0;
-	end = st_size - 1;
-
-	for (s = range, error = 0;
-	     !error && *s && NULL != (minus = strchr(s, '-')); ) {
-		char *err;
-		off_t la = 0, le;
-		*((const char **)&err) = s; /*(quiet clang --analyze)*/
-
-		if (s != minus) {
-			la = strtoll(s, &err, 10);
-			if (err != minus) {
-				/* should not have multiple range-unit in Range, but
-				 * handle just in case multiple Range headers merged */
-				while (*s == ' ' || *s == '\t') ++s;
-				if (0 != strncmp(s, "bytes=", 6)) return -1;
-				s += 6;
-				if (s != minus) {
-					la = strtoll(s, &err, 10);
-					if (err != minus) return -1;
-				}
-			}
-		}
-
-		if (s == minus) {
-			/* -<stop> */
-
-			le = strtoll(s, &err, 10);
-
-			if (le == 0) {
-				/* RFC 2616 - 14.35.1 */
-
-				r->http_status = 416;
-				error = 1;
-			} else if (*err == '\0') {
-				/* end */
-				s = err;
-
-				end = st_size - 1;
-				start = st_size + le;
-			} else if (*err == ',') {
-				s = err + 1;
-
-				end = st_size - 1;
-				start = st_size + le;
-			} else {
-				error = 1;
-			}
-
-		} else if (*(minus+1) == '\0' || *(minus+1) == ',') {
-			/* <start>- */
-
-				/* ok */
-
-				if (*(err + 1) == '\0') {
-					s = err + 1;
-
-					end = st_size - 1;
-					start = la;
-
-				} else if (*(err + 1) == ',') {
-					s = err + 2;
-
-					end = st_size - 1;
-					start = la;
-				} else {
-					error = 1;
-				}
-		} else {
-			/* <start>-<stop> */
-
-				le = strtoll(minus+1, &err, 10);
-
-				/* RFC 2616 - 14.35.1 */
-				if (la > le) {
-					error = 1;
-				}
-
-				if (*err == '\0') {
-					/* ok, end*/
-					s = err;
-
-					end = le;
-					start = la;
-				} else if (*err == ',') {
-					s = err + 1;
-
-					end = le;
-					start = la;
-				} else {
-					/* error */
-
-					error = 1;
-				}
-		}
-
-		if (!error) {
-			if (start < 0) start = 0;
-
-			/* RFC 2616 - 14.35.1 */
-			if (end > st_size - 1) end = st_size - 1;
-
-			if (start > st_size - 1) {
-				error = 1;
-
-				r->http_status = 416;
-			}
-		}
-
-		if (!error) {
-			if (n < (int)(sizeof(ranges)/sizeof(*ranges))) {
-				ranges[n] = start;
-				ranges[n+1] = end;
-				n += 2;
-			}
-			else { /* excessive num ranges in request */
-				error = 1;
-				r->http_status = 416;
-			}
-		}
-	}
-
-	/* something went wrong */
-	if (error) return -1;
-
-	if (n > 2) n = http_response_coalesce_ranges(ranges, n);
-
-	for (int i = 0; i < n; i += 2) {
-			start = ranges[i];
-			end = ranges[i+1];
-			if (n > 2) {
-				/* write boundary-header */
-				buffer *b = r->tmp_buf;
-				buffer_copy_string_len(b, CONST_STR_LEN("\r\n--"));
-				buffer_append_string_len(b, boundary, sizeof(boundary)-1);
-
-				/* write Content-Range */
-				buffer_append_string_len(b, CONST_STR_LEN("\r\nContent-Range: bytes "));
-				buffer_append_int(b, start);
-				buffer_append_string_len(b, CONST_STR_LEN("-"));
-				buffer_append_int(b, end);
-				buffer_append_string_len(b, CONST_STR_LEN("/"));
-				buffer_append_int(b, st_size);
-
-				if (content_type) {
-					buffer_append_string_len(b, CONST_STR_LEN("\r\nContent-Type: "));
-					buffer_append_string_buffer(b, content_type);
-				}
-
-				/* write END-OF-HEADER */
-				buffer_append_string_len(b, CONST_STR_LEN("\r\n\r\n"));
-				http_chunk_append_mem(r, CONST_BUF_LEN(b));
-			}
-
-			http_chunk_append_file_ref_range(r, sce, start, end - start + 1);
-	}
-
-	buffer * const tb = r->tmp_buf;
-
-	if (n > 2) {
-		/* add boundary end */
-		buffer_copy_string_len(tb, "\r\n--", 4);
-		buffer_append_string_len(tb, boundary, sizeof(boundary)-1);
-		buffer_append_string_len(tb, "--\r\n", 4);
-		http_chunk_append_mem(r, CONST_BUF_LEN(tb));
-
-		/* set header-fields */
-
-		buffer_copy_string_len(tb, CONST_STR_LEN("multipart/byteranges; boundary="));
-		buffer_append_string_len(tb, boundary, sizeof(boundary)-1);
-
-		/* overwrite content-type */
-		http_header_response_set(r, HTTP_HEADER_CONTENT_TYPE,
-		                         CONST_STR_LEN("Content-Type"),
-		                         CONST_BUF_LEN(tb));
-	} else {
-		/* add Content-Range-header */
-
-		buffer_copy_string_len(tb, CONST_STR_LEN("bytes "));
-		buffer_append_int(tb, start);
-		buffer_append_string_len(tb, CONST_STR_LEN("-"));
-		buffer_append_int(tb, end);
-		buffer_append_string_len(tb, CONST_STR_LEN("/"));
-		buffer_append_int(tb, st_size);
-
-		http_header_response_set(r, HTTP_HEADER_CONTENT_RANGE,
-		                         CONST_STR_LEN("Content-Range"),
-		                         CONST_BUF_LEN(tb));
-	}
-
-	/* ok, the file is set-up */
-	return 0;
-}
-
-
-__attribute_pure__
-static int http_response_match_if_range(request_st * const r, const buffer * const mtime) {
-    const buffer *vb = http_header_request_get(r, HTTP_HEADER_IF_RANGE,
-                                               CONST_STR_LEN("If-Range"));
-    return NULL == vb
-        || ((vb->ptr[0] == '"')
-            ? buffer_is_equal(vb, &r->physical.etag) /*compare ETag ("...") */
-            : mtime && buffer_is_equal(vb, mtime));  /*compare Last-Modified*/
-}
-
 void http_response_send_file (request_st * const r, buffer * const path) {
 	stat_cache_entry * const sce = stat_cache_get_entry_open(path, r->conf.follow_symlink);
 	const buffer *mtime = NULL;
-	const buffer *vb;
 	int allow_caching = (0 == r->http_status || 200 == r->http_status);
 
 	if (NULL == sce) {
@@ -630,15 +372,6 @@ void http_response_send_file (request_st * const r, buffer * const path) {
 		}
 	}
 
-	if (!http_method_get_or_head(r->http_method)
-	    || r->http_version < HTTP_VERSION_1_1)
-		r->conf.range_requests = 0;
-	if (r->conf.range_requests) {
-		http_header_response_append(r, HTTP_HEADER_ACCEPT_RANGES,
-		                            CONST_STR_LEN("Accept-Ranges"),
-		                            CONST_STR_LEN("bytes"));
-	}
-
 	if (allow_caching) {
 		if (!light_btst(r->resp_htags, HTTP_HEADER_ETAG)
 		    && 0 != r->conf.etag_flags) {
@@ -674,19 +407,6 @@ void http_response_send_file (request_st * const r, buffer * const path) {
 		return;
 	}
 
-	if (r->conf.range_requests
-	    && (200 == r->http_status || 0 == r->http_status)
-	    && NULL != (vb = http_header_request_get(r, HTTP_HEADER_RANGE,
-	                                             CONST_STR_LEN("Range")))
-	    && !light_btst(r->resp_htags, HTTP_HEADER_CONTENT_ENCODING)
-	    && http_response_match_if_range(r, mtime) /* "If-Range" */
-	    && !buffer_string_is_empty(vb) && 0 == strncmp(vb->ptr, "bytes=", 6)) {
-			r->resp_body_finished = 1;
-			if (0 == http_response_parse_range(r, sce, vb->ptr+6))
-				r->http_status = 206;
-			return;
-	}
-
 	/* if we are still here, prepare body */
 
 	/* we add it here for all requests
diff --git a/src/response.c b/src/response.c
index d243915d..7da19b11 100644
--- a/src/response.c
+++ b/src/response.c
@@ -11,6 +11,7 @@
 #include "chunk.h"
 #include "http_chunk.h"
 #include "http_date.h"
+#include "http_range.h"
 
 #include "plugin.h"
 
@@ -868,6 +869,10 @@ http_response_write_prepare(request_st * const r)
     }
 
     if (r->resp_body_finished) {
+        /* check for Range request (current impl requires resp_body_finished) */
+        if (r->conf.range_requests && http_range_rfc7233(r) >= 400)
+            http_response_static_errdoc(r); /* 416 Range Not Satisfiable */
+
         /* set content-length if length is known and not already set */
         if (!(r->resp_htags
               & (light_bshift(HTTP_HEADER_CONTENT_LENGTH)