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-rw-r--r--src/evaluate.c39
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;