diff options
| -rw-r--r-- | include/protocol.h | 106 | ||||
| -rw-r--r-- | src/common/protocol.c | 91 |
2 files changed, 80 insertions, 117 deletions
diff --git a/include/protocol.h b/include/protocol.h index e15ef6a..387424f 100644 --- a/include/protocol.h +++ b/include/protocol.h @@ -21,6 +21,41 @@ #ifndef USURPATION_PROTOCOL_H_INCLUDED #define USURPATION_PROTOCOL_H_INCLUDED +#if 0 + + How do we use this API(?), I hear you say. Well, here is a self-contained + example complete with tedious comments: + +------------------------------------------------------------------------------- + 1 | void functy_the_function(void) + 2 | { + 3 | struct tlv tlv_packet; /* A packet made of tlv's */ + 4 | struct tlv text; /* Actually useful data */ + 5 | char *packet; /* Raw bytes to be pushed via UDP */ + 6 | size_t packet_size; /* Raw packet size */ + 7 | char message[] = "Get jacked!"; /* Duh! */ + 9 | + 10 | tlv_init(&tlv_packet, REGURAL); /* Initialise tlv_packet to regular */ + 11 | tlv_init(&text, TEXT); /* Initialise text packet */ + 12 | tlv_push_data(&text, message, sizeof(message)); /* Push text to appropriate tlv */ + 13 | tlv_push_tlv(&tlv_packet, &text); /* Push the tlv into tlv packet */ + 14 | + 15 | packet_size = tlv_raw_size(&tlv_packet); /* Get raw size required to push entire tlv_packet as bytes */ + 16 | packet = (char *)malloc(packet_size); /* Allocate buffer for outgoing packet */ + 17 | tlv_get_raw(&tlv_packet, packet); /* Flash tlv_packet to buffer */ + 19 | udp_push(packet, packet_size); /* Push packet via UDP */ + 20 | udp_flush(); /* Flush to the other side*/ + 21 | + 22 | tlv_destroy(&text); /* Free text tlv */ + 23 | tlv_destroy(&tlv_packet); /* Free tlv_packet */ + 24 | free(packet); /* Free packet itself */ + 25 | return; /* GTFO and save stack space */ + 26 | } +------------------------------------------------------------------------------- + +#endif + + #include <errno.h> #define E_TLV_OVERFLOW (1 << 0) @@ -30,19 +65,6 @@ #define TLV_SZ_MAX_RAW (MTU - 64) /** - * Regular packets contain tlv's defined by tlv_type. - * - * Hearbeat packet tell daemon that device is still alive and listening. - * - * Discovery packets are used for what they say. - */ -enum packet_type { - REGURAL, - HEARTBEAT, - DISCOVERY -}; - -/** * Message sequence number since beggining of sesssion. * * Mainly used for identifying lost messages. @@ -77,20 +99,24 @@ enum tlv_type { /** * UUID that represents a particular device. */ - UUID -}; + UUID, -/** - * Packet data itself is a special type of tlv. A packet is either regular, - * hearbeat or discovery. - * - * May be used to send data. - */ -struct tlv_packet { - enum packet_type type; - size_t size; - size_t offset; - char *data; /* Bytes representing tlv's */ +/* Data of the following types are other tlv's! */ + + /** + * Just a TLV container. + */ + REGURAL, + + /** + * Says "I'm not dead yet.". + */ + HEARTBEAT, + + /** + * Says "Bring out yer dead!". + */ + DISCOVERY }; /** @@ -122,24 +148,6 @@ struct tlv_parser { int tlv_get(struct tlv_parser *parser, struct tlv *ret); /** - * Appends data to the next packet to be sent. Type of data is determined by - * enum tlv_type. - * - * In case of overflow return E_TLV_OVERFLOW. - * - * On next call after retreiving last packet returns END_OF_PACKET. - * - * Overflow can be detected after forming tlv header. This means that the - * packet may have changes. - * */ -int tlv_push_data(struct tlv_packet *packet, enum tlv_type type, char *data); - -/** - * Resets offset to 0 and set entire buffer to 0. - */ -void tlv_clear_data(struct tlv_packet *packet); - -/** * Initialises tlv to sane values. */ void tlv_init(struct tlv *t, enum tlv_type type); @@ -153,7 +161,7 @@ void tlv_destroy(struct tlv *t); /** * Tells amount of bytes needed to push tlv to a buffer */ -size_t tlv_raw_size(struct tlv *t); +size_t tlv_raw_size(const struct tlv *t); /** * Pushes tlv to buffer as contiguous data. Check tlv size with tlv_raw_size @@ -166,6 +174,12 @@ int tlv_get_raw(struct tlv *t, char *buf); * final size to be greater than TLV_SZ_MAX_RAW. In case of such error the data is left * untouched. */ -int tlv_push(struct tlv *t, const char *data, size_t size); +int tlv_push_data(struct tlv *t, const char *data, size_t size); + +/** + * Pushes a sub-tlv into the packet. 't' can only be REGURAL, HEARTBEAT or + * DISCOVERY. + */ +int tlv_push_tlv(struct tlv *t, const struct tlv *other); #endif /* USURPATION_PROTOCOL_H_INCLUDED */ diff --git a/src/common/protocol.c b/src/common/protocol.c index ed636d2..90dfc92 100644 --- a/src/common/protocol.c +++ b/src/common/protocol.c @@ -32,75 +32,6 @@ #include "net.h" #include "utils.h" -#if 0 -int tlv_push(struct tlv_packet *packet, enum tlv_type type, char *data) -{ - int ret = 0; - size_t size; - - switch (type) { - case TEXT: - size = strlen(data) + 1; - break; - case FPI1: - size = sizeof(fpi1_t); - break; - case TIMESTAMP: - size = sizeof(time_t); - break; - case REQUEST: - size = sizeof(msg_idx_t); - break; - case REPLY: - size = sizeof(msg_idx_t) + strlen(data + sizeof(msg_idx_t)); - break; - case UUID: - size = sizeof(uuid_t); - break; - default: - ret = E_UNKNOWN_TYPE; - } - ret |= push_tlv_header(packet, type, size); - ret |= push_bytes(packet, data, size); - return ret; -} - -#endif - -void tlv_clear_data(struct tlv_packet *packet) -{ - packet->offset = 0; - packet->type = 0; - memset(packet->data, 0, packet->size); -} - -static int push_bytes(struct tlv_packet *packet, char *data, size_t size) -{ - int ret = 0; - - if (packet->offset + size >= packet->size) { - ret = E_TLV_OVERFLOW; - } else { - memcpy(packet->data + packet->offset, data, size); - packet->offset += size; - } -} - -static int push_tlv_header(struct tlv_packet *packet, enum tlv_type type, size_t size) -{ - int ret = 0; - - if (packet->offset + sizeof(type) + sizeof(size) >= packet->size) { - ret = E_TLV_OVERFLOW; - } else { - memcpy(packet->data + packet->size, type, sizeof(type)); - packet->offset += sizeof(type); - memcpy(packet->data + packet->offset, size, sizeof(size)); - packet->offset += sizeof(size); - } - return ret; -} - int tlv_get(struct tlv_parser *parser, struct tlv *ret) { int retval = 0; @@ -141,12 +72,12 @@ void tlv_destroy(struct tlv *t) t->length = 0; } -size_t tlv_raw_size(struct tlv *t) +size_t tlv_raw_size(const struct tlv *t) { return sizeof(*t) + t->length; } -int tlv_push(struct tlv *t, const char *data, size_t size) +int tlv_push_data(struct tlv *t, const char *data, size_t size) { int ret = 0; size_t final_size = tlv_raw_size(t) + size; @@ -165,4 +96,22 @@ void tlv_init(struct tlv *t, enum tlv_type type) t->type = type; t->length = 0; t->data = NULL; +} + +int tlv_push_tlv(struct tlv *t, const struct tlv *other) +{ + int ret = 0; + size_t other_size; + size_t final_size; + + other_size = tlv_raw_size(other); + final_size = tlv_raw_size(t) + other_size; + if (final_size > TLV_SZ_MAX_RAW) { + ret = E_TLV_OVERFLOW; + } else { + tlv_get_raw(other, t->data + t->length); + t->length = final_size; + } + + return ret; }
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