diff options
| -rw-r--r-- | src/evaluate.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/src/evaluate.c b/src/evaluate.c index f2b6dd1e..87f5a6d7 100644 --- a/src/evaluate.c +++ b/src/evaluate.c @@ -1611,14 +1611,24 @@ static int stmt_evaluate_verdict(struct eval_ctx *ctx, struct stmt *stmt) return 0; } +static bool stmt_evaluate_payload_need_csum(const struct expr *payload) +{ + const struct proto_desc *desc; + + desc = payload->payload.desc; + + return desc && desc->checksum_key; +} + static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt) { struct expr *binop, *mask, *and, *payload_bytes; unsigned int masklen, extra_len = 0; - unsigned int payload_byte_size; + unsigned int payload_byte_size, payload_byte_offset; uint8_t shift_imm, data[NFT_REG_SIZE]; struct expr *payload; mpz_t bitmask, ff; + bool need_csum; if (__expr_evaluate_payload(ctx, stmt->payload.expr) < 0) return -1; @@ -1628,8 +1638,19 @@ static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt) &stmt->payload.val) < 0) return -1; - if (!payload_needs_adjustment(payload)) - return 0; + need_csum = stmt_evaluate_payload_need_csum(payload); + + if (!payload_needs_adjustment(payload)) { + + /* We still need to munge the payload in case we have to + * update checksum and the length is not even because + * kernel checksum functions cannot deal with odd lengths. + */ + if (!need_csum || ((payload->len / BITS_PER_BYTE) & 1) == 0) + return 0; + } + + payload_byte_offset = payload->payload.offset / BITS_PER_BYTE; shift_imm = expr_offset_shift(payload, payload->payload.offset, &extra_len); @@ -1651,6 +1672,16 @@ static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt) payload_byte_size = round_up(payload->len, BITS_PER_BYTE) / BITS_PER_BYTE; payload_byte_size += (extra_len / BITS_PER_BYTE); + + if (need_csum && payload_byte_size & 1) { + payload_byte_size++; + + if (payload_byte_offset & 1) { /* prefer 16bit aligned fetch */ + payload_byte_offset--; + assert(payload->payload.offset >= BITS_PER_BYTE); + } + } + masklen = payload_byte_size * BITS_PER_BYTE; mpz_init_bitmask(ff, masklen); @@ -1668,7 +1699,7 @@ static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt) payload_bytes = payload_expr_alloc(&payload->location, NULL, 0); payload_init_raw(payload_bytes, payload->payload.base, - (payload->payload.offset / BITS_PER_BYTE) * BITS_PER_BYTE, + payload_byte_offset * BITS_PER_BYTE, payload_byte_size * BITS_PER_BYTE); payload_bytes->payload.desc = payload->payload.desc; |