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authorMatthias Schiffer <mschiffer@universe-factory.net>2013-10-19 17:37:09 +0200
committerMatthias Schiffer <mschiffer@universe-factory.net>2013-10-19 17:37:09 +0200
commit0ce0b0449082d4ad54d1714d8683d7a9276b3b93 (patch)
tree2b6499b95b094ea5bfc89a99671bb056b5d5cda1 /src
parentc03f985b99f365d97c450a785dc75523d386020b (diff)
downloadfastd-0ce0b0449082d4ad54d1714d8683d7a9276b3b93.tar
fastd-0ce0b0449082d4ad54d1714d8683d7a9276b3b93.zip
Use the rsv2 field in the handshake header as an optional length field to facilitate future extensions
Diffstat (limited to 'src')
-rw-r--r--src/handshake.c34
-rw-r--r--src/handshake.h50
2 files changed, 44 insertions, 40 deletions
diff --git a/src/handshake.c b/src/handshake.c
index 47da0e4..82d47b8 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -98,10 +98,10 @@ fastd_buffer_t fastd_handshake_new_init(fastd_context_t *ctx, size_t tail_space)
4+method_list_len + /* supported method name list */
tail_space
);
- fastd_handshake_packet_t *request = buffer.data;
+ fastd_handshake_packet_t *packet = buffer.data;
- request->rsv1 = 0;
- request->rsv2 = 0;
+ packet->rsv = 0;
+ packet->tlv_len = 0;
fastd_handshake_add_uint8(ctx, &buffer, RECORD_HANDSHAKE_TYPE, 1);
fastd_handshake_add_uint8(ctx, &buffer, RECORD_MODE, ctx->conf->mode);
@@ -146,10 +146,10 @@ fastd_buffer_t fastd_handshake_new_reply(fastd_context_t *ctx, const fastd_hands
extra_size +
tail_space
);
- fastd_handshake_packet_t *request = buffer.data;
+ fastd_handshake_packet_t *packet = buffer.data;
- request->rsv1 = 0;
- request->rsv2 = 0;
+ packet->rsv = 0;
+ packet->tlv_len = 0;
fastd_handshake_add_uint8(ctx, &buffer, RECORD_HANDSHAKE_TYPE, AS_UINT8(handshake->records[RECORD_HANDSHAKE_TYPE])+1);
fastd_handshake_add_uint8(ctx, &buffer, RECORD_REPLY_CODE, 0);
@@ -186,15 +186,27 @@ void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fa
fastd_handshake_t handshake = { .buffer = buffer };
fastd_handshake_packet_t *packet = buffer.data;
- uint8_t *ptr = packet->tlv_data;
+ size_t len = buffer.len - sizeof(fastd_handshake_packet_t);
+ if (packet->tlv_len) {
+ size_t tlv_len = ntohs(packet->tlv_len);
+ if (tlv_len > len) {
+ pr_warn(ctx, "received a short handshake from %I", remote_addr);
+ goto end_free;
+ }
+
+ len = tlv_len;
+ }
+
+ uint8_t *ptr = packet->tlv_data, *end = packet->tlv_data + len;
+
while (true) {
- if (ptr+4 > (uint8_t*)buffer.data + buffer.len)
+ if (ptr+4 > end)
break;
uint16_t type = ptr[0] + (ptr[1] << 8);
uint16_t len = ptr[2] + (ptr[3] << 8);
- if (ptr+4+len > (uint8_t*)buffer.data + buffer.len)
+ if (ptr+4+len > end)
break;
if (type < RECORD_MAX) {
@@ -292,8 +304,8 @@ void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fa
fastd_buffer_t reply_buffer = fastd_buffer_alloc(ctx, sizeof(fastd_handshake_packet_t), 0, 3*5 /* enough space for handshake type, reply code and error detail */);
fastd_handshake_packet_t *reply = reply_buffer.data;
- reply->rsv1 = 0;
- reply->rsv2 = 0;
+ reply->rsv = 0;
+ reply->tlv_len = 0;
fastd_handshake_add_uint8(ctx, &reply_buffer, RECORD_HANDSHAKE_TYPE, 2);
fastd_handshake_add_uint8(ctx, &reply_buffer, RECORD_REPLY_CODE, reply_code);
diff --git a/src/handshake.h b/src/handshake.h
index 2fae1ad..e548be3 100644
--- a/src/handshake.h
+++ b/src/handshake.h
@@ -59,8 +59,8 @@ typedef enum fastd_reply_code {
typedef struct __attribute__((__packed__)) fastd_handshake_packet {
- uint8_t rsv1;
- uint16_t rsv2;
+ uint8_t rsv;
+ uint16_t tlv_len;
uint8_t tlv_data[];
} fastd_handshake_packet_t;
@@ -82,50 +82,42 @@ fastd_buffer_t fastd_handshake_new_reply(fastd_context_t *ctx, const fastd_hands
void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, fastd_buffer_t buffer);
-static inline void fastd_handshake_add(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, size_t len, const void *data) {
- if ((uint8_t*)buffer->data + buffer->len + 4 + len > (uint8_t*)buffer->base + buffer->base_len)
+static inline uint8_t* fastd_handshake_extend(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, size_t len) {
+ uint8_t *dst = buffer->data + buffer->len;
+
+ if (buffer->data + buffer->len + 4 + len > buffer->base + buffer->base_len)
exit_bug(ctx, "not enough buffer allocated for handshake");
- uint8_t *dst = (uint8_t*)buffer->data + buffer->len;
+ buffer->len += 4 + len;
+
+ fastd_handshake_packet_t *packet = buffer->data;
+ packet->tlv_len = htons(ntohs(packet->tlv_len) + 4 + len);
dst[0] = type;
dst[1] = type >> 8;
dst[2] = len;
dst[3] = len >> 8;
- memcpy(dst+4, data, len);
- buffer->len += 4 + len;
+ return dst+4;
}
-static inline void fastd_handshake_add_uint8(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, uint8_t value) {
- if ((uint8_t*)buffer->data + buffer->len + 5 > (uint8_t*)buffer->base + buffer->base_len)
- exit_bug(ctx, "not enough buffer allocated for handshake");
+static inline void fastd_handshake_add(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, size_t len, const void *data) {
+ uint8_t *dst = fastd_handshake_extend(ctx, buffer, type, len);
- uint8_t *dst = (uint8_t*)buffer->data + buffer->len;
+ memcpy(dst, data, len);
+}
- dst[0] = type;
- dst[1] = type >> 8;
- dst[2] = 1;
- dst[3] = 0;
- dst[4] = value;
+static inline void fastd_handshake_add_uint8(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, uint8_t value) {
+ uint8_t *dst = fastd_handshake_extend(ctx, buffer, type, 1);
- buffer->len += 5;
+ dst[0] = value;
}
static inline void fastd_handshake_add_uint16(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, uint16_t value) {
- if ((uint8_t*)buffer->data + buffer->len + 6 > (uint8_t*)buffer->base + buffer->base_len)
- exit_bug(ctx, "not enough buffer allocated for handshake");
-
- uint8_t *dst = (uint8_t*)buffer->data + buffer->len;
-
- dst[0] = type;
- dst[1] = type >> 8;
- dst[2] = 2;
- dst[3] = 0;
- dst[4] = value;
- dst[5] = value >> 8;
+ uint8_t *dst = fastd_handshake_extend(ctx, buffer, type, 2);
- buffer->len += 6;
+ dst[0] = value;
+ dst[1] = value >> 8;
}