forked from ElementsProject/lightning
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
features: more general accessor functions.
As we add more features, the current code is insufficient. 1. Keep an array of single feature bits, for easy switching on and off. 2. Create feature_offered() which checks for both compulsory and optional variants. 3. Invert requires_unsupported_features() and unsupported_features() which tend to be double-negative, all_supported_features() and features_supported(). 4. Move single feature definition from wire/peer_wire.h to common/features.h. Signed-off-by: Rusty Russell <[email protected]>
- Loading branch information
1 parent
1f443df
commit 46cc7c2
Showing
10 changed files
with
145 additions
and
82 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,62 +1,119 @@ | ||
| #include "features.h" | ||
| #include <assert.h> | ||
| #include <ccan/array_size/array_size.h> | ||
| #include <wire/peer_wire.h> | ||
|
|
||
| static const u8 supported_local_features[] | ||
| = {LOCALFEATURES_INITIAL_ROUTING_SYNC}; | ||
| static const u8 supported_global_features[] | ||
| = {}; | ||
| static const u32 local_features[] = { | ||
| LOCAL_INITIAL_ROUTING_SYNC | ||
| }; | ||
|
|
||
| u8 *get_supported_global_features(const tal_t *ctx) | ||
| static const u32 global_features[] = { | ||
| }; | ||
|
|
||
| static void set_bit(u8 **ptr, u32 bit) | ||
| { | ||
| return tal_dup_arr(ctx, u8, supported_global_features, | ||
| sizeof(supported_global_features), 0); | ||
| if (bit / 8 >= tal_len(*ptr)) | ||
| tal_resizez(ptr, (bit / 8) + 1); | ||
| (*ptr)[bit / 8] |= (1 << (bit % 8)); | ||
| } | ||
|
|
||
| /* We don't insist on anything, it's all optional. */ | ||
| static u8 *mkfeatures(const tal_t *ctx, const u32 *arr, size_t n) | ||
| { | ||
| u8 *f = tal_arr(ctx, u8, 0); | ||
|
|
||
| for (size_t i = 0; i < n; i++) | ||
| set_bit(&f, OPTIONAL_FEATURE(arr[i])); | ||
| return f; | ||
| } | ||
|
|
||
| u8 *get_supported_local_features(const tal_t *ctx) | ||
| u8 *get_offered_global_features(const tal_t *ctx) | ||
| { | ||
| return tal_dup_arr(ctx, u8, supported_local_features, | ||
| sizeof(supported_local_features), 0); | ||
| return mkfeatures(ctx, global_features, ARRAY_SIZE(global_features)); | ||
| } | ||
|
|
||
| u8 *get_offered_local_features(const tal_t *ctx) | ||
| { | ||
| return mkfeatures(ctx, local_features, ARRAY_SIZE(local_features)); | ||
| } | ||
|
|
||
| static bool test_bit(const u8 *features, size_t byte, unsigned int bit) | ||
| { | ||
| return features[byte] & (1 << (bit % 8)); | ||
| } | ||
|
|
||
| static bool feature_set(const u8 *features, size_t bit) | ||
| { | ||
| size_t bytenum = bit / 8; | ||
|
|
||
| if (bytenum >= tal_len(features)) | ||
| return false; | ||
|
|
||
| return test_bit(features, bytenum, bit % 8); | ||
| } | ||
|
|
||
| bool feature_offered(const u8 *features, size_t f) | ||
| { | ||
| assert(f % 2 == 0); | ||
|
|
||
| return feature_set(features, f) | ||
| || feature_set(features, OPTIONAL_FEATURE(f)); | ||
| } | ||
|
|
||
| static bool feature_supported(int feature_bit, | ||
| const u32 *supported, | ||
| size_t num_supported) | ||
| { | ||
| for (size_t i = 0; i < num_supported; i++) { | ||
| if (supported[i] == feature_bit) | ||
| return true; | ||
| } | ||
| return false; | ||
| } | ||
|
|
||
| /** | ||
| * requires_unsupported_features - Check if we support what's being asked | ||
| * all_supported_features - Check if we support what's being asked | ||
| * | ||
| * Given the features vector that the remote connection is expecting | ||
| * from us, we check to see if we support all even bit features, i.e., | ||
| * the required features. We do so by subtracting our own features in | ||
| * the provided positions and see if even bits remain. | ||
| * the required features. | ||
| * | ||
| * @bitmap: the features bitmap the peer is asking for | ||
| * @supportmap: what do we support | ||
| * @smlen: how long is our supportmap | ||
| * @supported: array of features we support | ||
| * @num_supported: how many elements in supported | ||
| */ | ||
| static bool requires_unsupported_features(const u8 *bitmap, | ||
| const u8 *supportmap, | ||
| size_t smlen) | ||
| static bool all_supported_features(const u8 *bitmap, | ||
| const u32 *supported, | ||
| size_t num_supported) | ||
| { | ||
| size_t len = tal_count(bitmap); | ||
| u8 support; | ||
| for (size_t i=0; i<len; i++) { | ||
| /* Find matching bitmap byte in supportmap, 0x00 if none */ | ||
| if (len > smlen) { | ||
| support = 0x00; | ||
| } else { | ||
| support = supportmap[smlen-1]; | ||
| } | ||
|
|
||
| /* Cancel out supported bits, check for even bits */ | ||
| if ((~support & bitmap[i]) & 0x55) | ||
| return true; | ||
|
|
||
| /* It's OK to be odd: only check even bits. */ | ||
| for (size_t bitnum = 0; bitnum < len; bitnum += 2) { | ||
| if (!test_bit(bitmap, bitnum/8, bitnum%8)) | ||
| continue; | ||
|
|
||
| if (feature_supported(bitnum, supported, num_supported)) | ||
| continue; | ||
|
|
||
| return false; | ||
| } | ||
| return false; | ||
| return true; | ||
| } | ||
|
|
||
| bool unsupported_features(const u8 *gfeatures, const u8 *lfeatures) | ||
| bool features_supported(const u8 *gfeatures, const u8 *lfeatures) | ||
| { | ||
| return requires_unsupported_features(gfeatures, | ||
| supported_global_features, | ||
| sizeof(supported_global_features)) | ||
| || requires_unsupported_features(lfeatures, | ||
| supported_local_features, | ||
| sizeof(supported_local_features)); | ||
| /* BIT 2 would logically be "compulsory initial_routing_sync", but | ||
| * that does not exist, so we special case it. */ | ||
| if (feature_set(lfeatures, | ||
| COMPULSORY_FEATURE(LOCAL_INITIAL_ROUTING_SYNC))) | ||
| return false; | ||
|
|
||
| return all_supported_features(gfeatures, | ||
| global_features, | ||
| ARRAY_SIZE(global_features)) | ||
| || all_supported_features(lfeatures, | ||
| local_features, | ||
| ARRAY_SIZE(local_features)); | ||
| } | ||
|
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters