bitwise: add support for left- and right-shifts.

The kernel supports bitwise shifts.  Add support to libnftnl.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/expr/bitwise.c b/src/expr/bitwise.c
index 6ea39fb..9ea2f66 100644
--- a/src/expr/bitwise.c
+++ b/src/expr/bitwise.c
@@ -233,6 +233,25 @@ nftnl_expr_bitwise_snprintf_bool(char *buf, size_t size,
 	return offset;
 }
 
+static int
+nftnl_expr_bitwise_snprintf_shift(char *buf, size_t size, const char *op,
+				  const struct nftnl_expr_bitwise *bitwise)
+{	int remain = size, offset = 0, ret;
+
+	ret = snprintf(buf, remain, "reg %u = ( reg %u %s ",
+		       bitwise->dreg, bitwise->sreg, op);
+	SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+
+	ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->data,
+				      NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
+	SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+
+	ret = snprintf(buf + offset, remain, ") ");
+	SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+
+	return offset;
+}
+
 static int nftnl_expr_bitwise_snprintf_default(char *buf, size_t size,
 					       const struct nftnl_expr *e)
 {
@@ -244,7 +263,10 @@ static int nftnl_expr_bitwise_snprintf_default(char *buf, size_t size,
 		err = nftnl_expr_bitwise_snprintf_bool(buf, size, bitwise);
 		break;
 	case NFT_BITWISE_LSHIFT:
+		err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", bitwise);
+		break;
 	case NFT_BITWISE_RSHIFT:
+		err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", bitwise);
 		break;
 	}