Beispiel #1
0
size_t
thex_upload_get_content_length(const shared_file_t *sf)
{
	const struct tth *tth;
	size_t n_leaves, n_nodes;
	size_t size = 0;

	g_return_val_if_fail(sf, 0);

	tth = shared_file_tth(sf);
	g_return_val_if_fail(tth, 0);

	size += thex_upload_prepare_xml(NULL, tth, shared_file_size(sf));

	n_nodes = 1;
	n_leaves = tt_good_node_count(shared_file_size(sf));
	while (n_leaves > 1) {
		n_nodes += n_leaves;
		n_leaves = (n_leaves + 1) / 2;
	}

	size += thex_upload_prepare_tree(NULL, tth, NULL, n_nodes);

	return size;
}
Beispiel #2
0
bool
huge_update_hashes(shared_file_t *sf,
	const struct sha1 *sha1, const struct tth *tth)
{
	struct sha1_cache_entry *cached;
	filestat_t sb;

	shared_file_check(sf);
	g_return_val_if_fail(sha1, FALSE);

	/*
	 * Make sure the file's timestamp is still accurate.
	 */

	if (-1 == stat(shared_file_path(sf), &sb)) {
		g_warning("discarding SHA1 for file \"%s\": can't stat(): %m",
			shared_file_path(sf));
		shared_file_remove(sf);
		return TRUE;
	}

	if (sb.st_mtime != shared_file_modification_time(sf)) {
		g_warning("file \"%s\" was modified whilst SHA1 was computed",
			shared_file_path(sf));
		shared_file_set_modification_time(sf, sb.st_mtime);
		request_sha1(sf);					/* Retry! */
		return TRUE;
	}

	if (huge_spam_check(sf, sha1)) {
		shared_file_remove(sf);
		return FALSE;
	}

	shared_file_set_sha1(sf, sha1);
	shared_file_set_tth(sf, tth);

	/* Update cache */

	cached = hikset_lookup(sha1_cache, shared_file_path(sf));

	if (cached) {
		update_volatile_cache(cached, shared_file_size(sf),
			shared_file_modification_time(sf), sha1, tth);
		cache_dirty = TRUE;

		/* Dump the cache at most about once per minute. */
		if (!cache_dumped || delta_time(tm_time(), cache_dumped) > 60) {
			dump_cache(FALSE);
		}
	} else {
		add_volatile_cache_entry(shared_file_path(sf),
			shared_file_size(sf), shared_file_modification_time(sf),
			sha1, tth, TRUE);
		add_persistent_cache_entry(shared_file_path(sf),
			shared_file_size(sf), shared_file_modification_time(sf),
			sha1, tth);
	}
	return TRUE;
}
Beispiel #3
0
/**
 * Check to see if an (in-memory) entry cache is up to date.
 *
 * @return true (in the C sense) if it is, or false otherwise.
 */
static bool
cached_entry_up_to_date(const struct sha1_cache_entry *cache_entry,
	const shared_file_t *sf)
{
	return cache_entry->size == shared_file_size(sf)
		&& cache_entry->mtime == shared_file_modification_time(sf);
}
Beispiel #4
0
void
request_tigertree(shared_file_t *sf, bool high_priority)
{
	int inserted;

	verify_tth_init();

	shared_file_check(sf);
	g_return_if_fail(shared_file_is_finished(sf));

	if (!shared_file_is_servable(sf))
		return;		/* "stale" shared file, has been superseded or removed */

	/*
	 * This routine can be called when the VERIFY_DONE event is received by
	 * huge_verify_callback().  We may have already shutdown the TTH
	 * verification thread.
	 */

	if G_UNLIKELY(NULL == verify_tth.verify)
		return;

	sf = shared_file_ref(sf);

	inserted = verify_enqueue(verify_tth.verify, high_priority,
					shared_file_path(sf), 0, shared_file_size(sf),
					request_tigertree_callback, sf);

	if (!inserted)
		shared_file_unref(&sf);
}
Beispiel #5
0
/**
 * Add `comp' to the current completed count, and update the amount of
 * bytes transferred.  Note that `comp' can be zero.
 * When `update_dtime' is TRUE, we update the "done time", otherwise we
 * change the "last request time".
 *
 * If the row does not exist (race condition: deleted since upload started),
 * recreate one.
 */
static void
upload_stats_file_add(
	const shared_file_t *sf,
	int comp, guint64 sent, gboolean update_dtime)
{
	const char *pathname = shared_file_path(sf);
	filesize_t size = shared_file_size(sf);
	struct ul_stats *s;
	const struct sha1 *sha1;

	g_assert(comp >= 0);

	sha1 = sha1_hash_available(sf) ? shared_file_sha1(sf) : NULL;

	/* find this file in the ul_stats_clist */
	s = upload_stats_find(sha1, pathname, size);

	/* increment the completed counter */
	if (NULL == s) {
		/* uh oh, row has since been deleted, add it: 1 attempt */
		upload_stats_add(pathname, size, shared_file_name_nfc(sf),
			1, comp, sent, tm_time(), tm_time(), sha1);
	} else {
		s->bytes_sent += sent;
		s->norm = 1.0 * s->bytes_sent / s->size;
		s->complete += comp;
		if (update_dtime)
			s->dtime = tm_time();
		else
			s->rtime = tm_time();
		gcu_upload_stats_gui_update(s);
	}

	dirty = TRUE;		/* Request asynchronous save of stats */
}
Beispiel #6
0
/**
 * Called when an upload starts.
 */
void
upload_stats_file_begin(const shared_file_t *sf)
{
	struct ul_stats *s;
	const char *pathname;
	filesize_t size;
	const struct sha1 *sha1;

	g_return_if_fail(sf);
	pathname = shared_file_path(sf);
	size = shared_file_size(sf);
	sha1 = sha1_hash_available(sf) ? shared_file_sha1(sf) : NULL;

	/* find this file in the ul_stats_clist */
	s = upload_stats_find(sha1, pathname, size);

	/* increment the attempted counter */
	if (NULL == s) {
		upload_stats_add(pathname, size, shared_file_name_nfc(sf),
			1, 0, 0, tm_time(), 0, sha1);
	} else {
		s->attempts++;
		s->rtime = tm_time();
		gcu_upload_stats_gui_update(s);
	}

	dirty = TRUE;		/* Request asynchronous save of stats */
}
Beispiel #7
0
/**
 * Creates a new THEX upload context. The context must be freed with
 * thex_upload_close().
 *
 * @param owner			the owner of the TX stack (the upload)
 * @param host			the host to which we're talking to
 * @param writable		no document
 * @param link_cb		callbacks for the link layer
 * @param wio			no document
 * @param flags			opening flags
 *
 * @return An initialized THEX upload context.
 */
struct special_upload *
thex_upload_open(
	void *owner,
	const struct gnutella_host *host,
	const shared_file_t *sf,
	special_upload_writable_t writable,
	const struct tx_link_cb *link_cb,
	struct wrap_io *wio,
	int flags)
{
	struct thex_upload *ctx;

	WALLOC(ctx);
	ctx->special_upload.read =  thex_upload_read;
	ctx->special_upload.write = thex_upload_write;
	ctx->special_upload.flush = thex_upload_flush;
	ctx->special_upload.close = thex_upload_close;

	ctx->tth = atom_tth_get(shared_file_tth(sf));
	ctx->filesize = shared_file_size(sf);
	ctx->data = NULL;
	ctx->size = 0;
	ctx->offset = 0;
	ctx->state = THEX_STATE_INITIAL;

	/*
	 * Instantiate the TX stack.
	 */

	{
		struct tx_link_args args;

		args.cb = link_cb;
		args.wio = wio;
		args.bws = bsched_out_select_by_addr(gnet_host_get_addr(host));

		ctx->tx = tx_make(owner, host, tx_link_get_ops(), &args);
	}

	if (flags & THEX_UPLOAD_F_CHUNKED) {
		ctx->tx = tx_make_above(ctx->tx, tx_chunk_get_ops(), 0);
	}

	/*
	 * Put stack in "eager" mode: we want to be notified whenever
	 * we can write something.
	 */

	tx_srv_register(ctx->tx, writable, owner);
	tx_eager_mode(ctx->tx, TRUE);

	/*
	 * Update statistics.
	 */

	gnet_prop_incr_guint32(PROP_THEX_FILES_REQUESTED);
	return &ctx->special_upload;
}
Beispiel #8
0
static bool 
request_tigertree_callback(const struct verify *ctx, enum verify_status status,
	void *user_data)
{
	shared_file_t *sf = user_data;

	shared_file_check(sf);
	switch (status) {
	case VERIFY_START:
		if (!(SHARE_F_INDEXED & shared_file_flags(sf))) {
			/*
			 * After a rescan, there might be files in the queue which are
			 * no longer shared.
			 */

			if (GNET_PROPERTY(verify_debug) > 1) {
				g_debug("skipping TTH computation for %s: no longer shared",
					shared_file_path(sf));
			}
			return FALSE;
		}
		if (
			shared_file_tth(sf) &&
			tth_cache_lookup(shared_file_tth(sf), shared_file_size(sf)) > 0
		) {
			if (
				GNET_PROPERTY(tigertree_debug) > 1 ||
				GNET_PROPERTY(verify_debug) > 1
			) {
				g_debug("TTH for %s is already cached (%s)",
					shared_file_path(sf), tth_base32(shared_file_tth(sf)));
			}
			return FALSE;
		}
		gnet_prop_set_boolean_val(PROP_TTH_REBUILDING, TRUE);
		return TRUE;
	case VERIFY_PROGRESS:
		return 0 != (SHARE_F_INDEXED & shared_file_flags(sf));
	case VERIFY_DONE:
		{
			const struct tth *tth = verify_tth_digest(ctx);
			
			huge_update_hashes(sf, shared_file_sha1(sf), tth);
			tth_cache_insert(tth, verify_tth_leaves(ctx),
				verify_tth_leave_count(ctx));
		}
		/* FALL THROUGH */
	case VERIFY_ERROR:
	case VERIFY_SHUTDOWN:
		shared_file_unref(&sf);
		gnet_prop_set_boolean_val(PROP_TTH_REBUILDING, FALSE);
		return TRUE;
	case VERIFY_INVALID:
		break;
	}
	g_assert_not_reached();
	return FALSE;
}
Beispiel #9
0
/**
 * Put the shared file on the stack of the things to do.
 *
 * We first begin with the computation of the SHA1, and when completed we
 * will continue with the TTH computation.
 */
static void
queue_shared_file_for_sha1_computation(shared_file_t *sf)
{
	int inserted;
	
 	shared_file_check(sf);

	inserted = verify_sha1_enqueue(FALSE, shared_file_path(sf),
					shared_file_size(sf), huge_verify_callback,
					shared_file_ref(sf));

	if (!inserted)
		shared_file_unref(&sf);
}
Beispiel #10
0
static bool
huge_spam_check(shared_file_t *sf, const struct sha1 *sha1)
{
	if (NULL != sha1 && spam_sha1_check(sha1)) {
		g_warning("file \"%s\" is listed as spam (SHA1)", shared_file_path(sf));
		return TRUE;
	}

	if (
		spam_check_filename_size(shared_file_name_nfc(sf),
			shared_file_size(sf))
	) {
		g_warning("file \"%s\" is listed as spam (Name)", shared_file_path(sf));
		return TRUE;
	}
	return FALSE;
}
Beispiel #11
0
void
request_tigertree(shared_file_t *sf, bool high_priority)
{
	int inserted;

	verify_tth_init();

	g_return_if_fail(sf);
	shared_file_check(sf);
	g_return_if_fail(!shared_file_is_partial(sf));

	sf = shared_file_ref(sf);

	inserted = verify_enqueue(verify_tth.verify, high_priority,
					shared_file_path(sf), 0, shared_file_size(sf),
					request_tigertree_callback, sf);

	if (!inserted)
		shared_file_unref(&sf);
}
Beispiel #12
0
/**
 * Writes the browse host data of the context ``ctx'' to the buffer
 * ``dest''. This must be called multiple times to retrieve the complete
 * data until zero is returned i.e., the end of file is reached.
 *
 * This routine deals with HTML data generation.
 *
 * @param ctx an initialized browse host context.
 * @param dest the destination buffer.
 * @param size the amount of bytes ``dest'' can hold.
 *
 * @return -1 on failure, zero at the end-of-file condition or if size
 *         was zero. On success, the amount of bytes copied to ``dest''
 *         is returned.
 */
static ssize_t
browse_host_read_html(struct special_upload *ctx,
	void *const dest, size_t size)
{
	static const char header[] =
		"<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\r\n"
		"<html>\r\n"
		"<head>\r\n"
		"<title>Browse Host</title>\r\n"
		"</head>\r\n"
		"<body>\r\n";
	static const char trailer[] = "</ul>\r\n</body>\r\n</html>\r\n";
	struct browse_host_upload *bh = cast_to_browse_host_upload(ctx);
	char *p = dest;

	g_assert(NULL != bh);
	g_assert(NULL != dest);
	g_assert(size <= INT_MAX);

	g_assert(UNSIGNED(bh->state) < NUM_BH_STATES);
	g_assert(bh->b_size <= INT_MAX);
	g_assert(bh->b_offset <= bh->b_size);

	do {
		switch (bh->state) {
		case BH_STATE_HEADER:
			if (!bh->b_data) {
				bh->b_data = header;
				bh->b_size = CONST_STRLEN(header);
			}
			p += browse_host_read_data(bh, p, &size);
			if (bh->b_size == bh->b_offset)
				browse_host_next_state(bh, BH_STATE_LIBRARY_INFO);
			break;

		case BH_STATE_LIBRARY_INFO:
			if (!bh->b_data) {
				bh->w_buf_size = w_concat_strings(&bh->w_buf,
					"<h1>", product_get_name(), "</h1>\r\n"
					"<h3>", version_get_string(),
				   	" sharing ",
					uint64_to_string(shared_files_scanned()),
					" file",
					shared_files_scanned() == 1 ? "" : "s",
					" ",
					short_kb_size(shared_kbytes_scanned(),
						GNET_PROPERTY(display_metric_units)),
					" total</h3>\r\n"
					"<ul>\r\n", (void *) 0);
				bh->b_data = bh->w_buf;
				bh->b_size = bh->w_buf_size - 1; /* minus trailing NUL */
				bh->b_offset = 0;
			}
			p += browse_host_read_data(bh, p, &size);
			if (bh->b_size == bh->b_offset)
				browse_host_next_state(bh, BH_STATE_FILES);
			break;

		case BH_STATE_TRAILER:
			if (!bh->b_data) {
				bh->b_data = trailer;
				bh->b_size = CONST_STRLEN(trailer);
			}
			p += browse_host_read_data(bh, p, &size);
			if (bh->b_size == bh->b_offset)
				browse_host_next_state(bh, BH_STATE_EOF);
			break;

		case BH_STATE_FILES:
			if (bh->b_data && bh->b_size == bh->b_offset) {
				g_assert(bh->w_buf == bh->b_data);
				wfree(bh->w_buf, bh->w_buf_size);
				bh->w_buf = NULL;
				bh->w_buf_size = 0;
				bh->b_data = NULL;
			}

			if (!bh->b_data) {
				const shared_file_t *sf;

				bh->file_index++;
				sf = shared_file_sorted(bh->file_index);
				if (!sf) {
				   	if (bh->file_index > shared_files_scanned())
						browse_host_next_state(bh, BH_STATE_TRAILER);
					/* Skip holes in the file_index table */
				} else if (SHARE_REBUILDING == sf) {
					browse_host_next_state(bh, BH_STATE_REBUILDING);
				} else {
					const char * const name_nfc = shared_file_name_nfc(sf);
					const filesize_t file_size = shared_file_size(sf);
					size_t html_size;
					char *html_name;

					{
						const char *dir;
						char *name;
						
						dir = shared_file_relative_path(sf);
						if (dir) {
							name = h_strconcat(dir, "/", name_nfc, (void *) 0);
						} else {
							name = deconstify_char(name_nfc);
						}

						html_size = 1 + html_escape(name, NULL, 0);
						html_name = walloc(html_size);
						html_escape(name, html_name, html_size);
						if (name != name_nfc) {
							HFREE_NULL(name);
						}
					}

					if (sha1_hash_available(sf)) {
						const struct sha1 *sha1 = shared_file_sha1(sf);

						bh->w_buf_size = w_concat_strings(&bh->w_buf,
							"<li><a href=\"/uri-res/N2R?urn:sha1:",
							sha1_base32(sha1),
							"\">", html_name, "</a>&nbsp;[",
							short_html_size(file_size,
								GNET_PROPERTY(display_metric_units)),
							"]</li>\r\n",
							(void *) 0);
					} else {
						char *escaped;

						escaped = url_escape(name_nfc);
						bh->w_buf_size = w_concat_strings(&bh->w_buf,
							"<li><a href=\"/get/",
							uint32_to_string(shared_file_index(sf)),
							"/", escaped, "\">", html_name, "</a>"
							"&nbsp;[",
							short_html_size(file_size,
								GNET_PROPERTY(display_metric_units)),
							"]</li>\r\n", (void *) 0);

						if (escaped != name_nfc) {
							HFREE_NULL(escaped);
						}
					}

					wfree(html_name, html_size);
					bh->b_data = bh->w_buf;
					bh->b_size = bh->w_buf_size - 1; /* minus trailing NUL */
					bh->b_offset = 0;
				}
			}

			if (bh->b_data)
				p += browse_host_read_data(bh, p, &size);

			break;

		case BH_STATE_REBUILDING:
			if (!bh->b_data) {
				static const char msg[] =
					"<li>"
						"<b>"
							"The library is currently being rebuild. Please, "
							"try again in a moment."
						"</b>"
					"</li>";

				bh->b_data = msg;
				bh->b_size = CONST_STRLEN(msg);
			}
			p += browse_host_read_data(bh, p, &size);
			if (bh->b_size == bh->b_offset)
				browse_host_next_state(bh, BH_STATE_TRAILER);
			break;

		case BH_STATE_EOF:
			return p - cast_to_char_ptr(dest);

		case NUM_BH_STATES:
			g_assert_not_reached();
		}
	} while (size > 0);

	return p - cast_to_char_ptr(dest);
}
Beispiel #13
0
/**
 * Add file to the current query hit.
 *
 * @return TRUE if we kept the file, FALSE if we did not include it in the hit.
 */
static bool
g2_build_qh2_add(struct g2_qh2_builder *ctx, const shared_file_t *sf)
{
	const sha1_t *sha1;
	g2_tree_t *h, *c;

	shared_file_check(sf);

	/*
	 * Make sure the file is still in the library.
	 */

	if (0 == shared_file_index(sf))
		return FALSE;

	/*
	 * On G2, the H/URN child is required, meaning we need the SHA1 at least.
	 */

	if (!sha1_hash_available(sf))
		return FALSE;

	/*
	 * Do not send duplicates, as determined by the SHA1 of the resource.
	 *
	 * A user may share several files with different names but the same SHA1,
	 * and if all of them are hits, we only want to send one instance.
	 *
	 * When generating hits for host-browsing, we do not care about duplicates
	 * and ctx->hs is NULL then.
	 */

	sha1 = shared_file_sha1(sf);		/* This is an atom */

	if (ctx->hs != NULL) {
		if (hset_contains(ctx->hs, sha1))
			return FALSE;

		hset_insert(ctx->hs, sha1);
	}

	/*
	 * Create the "H" child and attach it to the current tree.
	 */

	if (NULL == ctx->t)
		g2_build_qh2_start(ctx);

	h = g2_tree_alloc_empty("H");
	g2_tree_add_child(ctx->t, h);

	/*
	 * URN -- Universal Resource Name
	 *
	 * If there is a known TTH, then we can generate a bitprint, otherwise
	 * we just convey the SHA1.
	 */

	{
		const tth_t * const tth = shared_file_tth(sf);
		char payload[SHA1_RAW_SIZE + TTH_RAW_SIZE + sizeof G2_URN_BITPRINT];
		char *p = payload;

		if (NULL == tth) {
			p = mempcpy(p, G2_URN_SHA1, sizeof G2_URN_SHA1);
			p += clamp_memcpy(p, sizeof payload - ptr_diff(p, payload),
				sha1, SHA1_RAW_SIZE);
		} else {
			p = mempcpy(p, G2_URN_BITPRINT, sizeof G2_URN_BITPRINT);
			p += clamp_memcpy(p, sizeof payload - ptr_diff(p, payload),
				sha1, SHA1_RAW_SIZE);
			p += clamp_memcpy(p, sizeof payload - ptr_diff(p, payload),
				tth, TTH_RAW_SIZE);
		}

		g_assert(ptr_diff(p, payload) <= sizeof payload);

		c = g2_tree_alloc_copy("URN", payload, ptr_diff(p, payload));
		g2_tree_add_child(h, c);
	}

	/*
	 * URL -- empty to indicate that we share the file via uri-res.
	 */

	if (ctx->flags & QHIT_F_G2_URL) {
		uint known;
		uint16 csc;

		c = g2_tree_alloc_empty("URL");
		g2_tree_add_child(h, c);

		/*
		 * CSC -- if we know alternate sources, indicate how many in "CSC".
		 *
		 * This child is only emitted when they requested "URL".
		 */

		known = dmesh_count(sha1);
		csc = MIN(known, MAX_INT_VAL(uint16));

		if (csc != 0) {
			char payload[2];

			poke_le16(payload, csc);
			c = g2_tree_alloc_copy("CSC", payload, sizeof payload);
			g2_tree_add_child(h, c);
		}

		/*
		 * PART -- if we only have a partial file, indicate how much we have.
		 *
		 * This child is only emitted when they requested "URL".
		 */

		if (shared_file_is_partial(sf) && !shared_file_is_finished(sf)) {
			filesize_t available = shared_file_available(sf);
			char payload[8];	/* If we have to encode file size as 64-bit */
			uint32 av32;
			time_t mtime = shared_file_modification_time(sf);

			c = g2_tree_alloc_empty("PART");
			g2_tree_add_child(h, c);

			av32 = available;
			if (av32 == available) {
				/* Fits within a 32-bit quantity */
				poke_le32(payload, av32);
				g2_tree_set_payload(c, payload, sizeof av32, TRUE);
			} else {
				/* Encode as a 64-bit quantity then */
				poke_le64(payload, available);
				g2_tree_set_payload(c, payload, sizeof payload, TRUE);
			}

			/*
			 * GTKG extension: encode the last modification time of the
			 * partial file in an "MT" child.  This lets the other party
			 * determine whether the host is still able to actively complete
			 * the file.
			 */

			poke_le32(payload, (uint32) mtime);
			g2_tree_add_child(c,
				g2_tree_alloc_copy("MT", payload, sizeof(uint32)));
		}

		/*
		 * CT -- creation time of the resource (GTKG extension).
		 */

		{
			time_t create_time = shared_file_creation_time(sf);

			if ((time_t) -1 != create_time) {
				char payload[8];
				int n;

				create_time = MAX(0, create_time);
				n = vlint_encode(create_time, payload);
				g2_tree_add_child(h,
					g2_tree_alloc_copy("CT", payload, n));	/* No trailing 0s */
			}
		}
	}

	/*
	 * DN -- distinguished name.
	 *
	 * Note that the presence of DN also governs the presence of SZ if the
	 * file length does not fit a 32-bit unsigned quantity.
	 */

	if (ctx->flags & QHIT_F_G2_DN) {
		char payload[8];		/* If we have to encode file size as 64-bit */
		uint32 fs32;
		filesize_t fs = shared_file_size(sf);
		const char *name;
		const char *rp;

		c = g2_tree_alloc_empty("DN");

		fs32 = fs;
		if (fs32 == fs) {
			/* Fits within a 32-bit quantity */
			poke_le32(payload, fs32);
			g2_tree_set_payload(c, payload, sizeof fs32, TRUE);
		} else {
			/* Does not fit a 32-bit quantity, emit a SZ child */
			poke_le64(payload, fs);
			g2_tree_add_child(h,
				g2_tree_alloc_copy("SZ", payload, sizeof payload));
		}

		name = shared_file_name_nfc(sf);
		g2_tree_append_payload(c, name, shared_file_name_nfc_len(sf));
		g2_tree_add_child(h, c);

		/*
		 * GTKG extension: if there is a file path, expose it as a "P" child
		 * under the DN node.
		 */

		rp = shared_file_relative_path(sf);
		if (rp != NULL) {
			g2_tree_add_child(c, g2_tree_alloc_copy("P", rp, strlen(rp)));
		}
	}

	/*
	 * GTKG extension: if they requested alt-locs in the /Q2/I with "A", then
	 * send them some known alt-locs in an "ALT" child.
	 *
	 * Note that these alt-locs can be for Gnutella hosts: since both Gnutella
	 * and G2 share a common HTTP-based file transfer mechanism with compatible
	 * extra headers, there is no need to handle them separately.
	 */

	if (ctx->flags & QHIT_F_G2_ALT) {
		gnet_host_t hvec[G2_BUILD_QH2_MAX_ALT];
		int hcnt = 0;

		hcnt = dmesh_fill_alternate(sha1, hvec, N_ITEMS(hvec));

		if (hcnt > 0) {
			int i;

			c = g2_tree_alloc_empty("ALT");

			for (i = 0; i < hcnt; i++) {
				host_addr_t addr;
				uint16 port;

				addr = gnet_host_get_addr(&hvec[i]);
				port = gnet_host_get_port(&hvec[i]);

				if (host_addr_is_ipv4(addr)) {
					char payload[6];

					host_ip_port_poke(payload, addr, port, NULL);
					g2_tree_append_payload(c, payload, sizeof payload);
				}
			}

			/*
			 * If the payload is still empty, then drop the "ALT" child.
			 * Otherwise, attach it to the "H" node.
			 */

			if (NULL == g2_tree_node_payload(c, NULL)) {
				g2_tree_free_null(&c);
			} else {
				g2_tree_add_child(h, c);
			}
		}
	}

	/*
	 * Update the size of the query hit we're generating.
	 */

	ctx->current_size += g2_frame_serialize(h, NULL, 0);

	return TRUE;
}