From f683f636a0aa8b121a9153c96cf5ca3f8e76faa5 Mon Sep 17 00:00:00 2001 From: Jeremy Sowden Date: Wed, 13 Nov 2024 22:27:08 +0100 Subject: expr: bitwise: add support for kernel space AND, OR and XOR operations Hitherto, the kernel has only supported boolean operations of the form: dst = (src & mask) ^ xor where `src` is held in a register, and `mask` and `xor` are immediate values. User space has converted AND, OR and XOR operations to this form, and so one operand has had to be immediate. The kernel now supports performing AND, OR and XOR operations directly, on one register and an immediate value or on two registers, so we make that support available to user space. Signed-off-by: Jeremy Sowden Signed-off-by: Pablo Neira Ayuso --- src/expr/bitwise.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 55 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/expr/bitwise.c b/src/expr/bitwise.c index 9385219..cac47a5 100644 --- a/src/expr/bitwise.c +++ b/src/expr/bitwise.c @@ -19,6 +19,7 @@ struct nftnl_expr_bitwise { enum nft_registers sreg; + enum nft_registers sreg2; enum nft_registers dreg; enum nft_bitwise_ops op; unsigned int len; @@ -37,6 +38,9 @@ nftnl_expr_bitwise_set(struct nftnl_expr *e, uint16_t type, case NFTNL_EXPR_BITWISE_SREG: memcpy(&bitwise->sreg, data, data_len); break; + case NFTNL_EXPR_BITWISE_SREG2: + memcpy(&bitwise->sreg2, data, sizeof(bitwise->sreg2)); + break; case NFTNL_EXPR_BITWISE_DREG: memcpy(&bitwise->dreg, data, data_len); break; @@ -66,6 +70,9 @@ nftnl_expr_bitwise_get(const struct nftnl_expr *e, uint16_t type, case NFTNL_EXPR_BITWISE_SREG: *data_len = sizeof(bitwise->sreg); return &bitwise->sreg; + case NFTNL_EXPR_BITWISE_SREG2: + *data_len = sizeof(bitwise->sreg2); + return &bitwise->sreg2; case NFTNL_EXPR_BITWISE_DREG: *data_len = sizeof(bitwise->dreg); return &bitwise->dreg; @@ -98,6 +105,7 @@ static int nftnl_expr_bitwise_cb(const struct nlattr *attr, void *data) switch(type) { case NFTA_BITWISE_SREG: + case NFTA_BITWISE_SREG2: case NFTA_BITWISE_DREG: case NFTA_BITWISE_OP: case NFTA_BITWISE_LEN: @@ -123,6 +131,8 @@ nftnl_expr_bitwise_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG)) mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG, htonl(bitwise->sreg)); + if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG2)) + mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG2, htonl(bitwise->sreg2)); if (e->flags & (1 << NFTNL_EXPR_BITWISE_DREG)) mnl_attr_put_u32(nlh, NFTA_BITWISE_DREG, htonl(bitwise->dreg)); if (e->flags & (1 << NFTNL_EXPR_BITWISE_OP)) @@ -169,6 +179,10 @@ nftnl_expr_bitwise_parse(struct nftnl_expr *e, struct nlattr *attr) bitwise->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG])); e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG); } + if (tb[NFTA_BITWISE_SREG2]) { + bitwise->sreg2 = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG2])); + e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG2); + } if (tb[NFTA_BITWISE_DREG]) { bitwise->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_DREG])); e->flags |= (1 << NFTNL_EXPR_BITWISE_DREG); @@ -240,6 +254,31 @@ nftnl_expr_bitwise_snprintf_shift(char *buf, size_t remain, const char *op, return offset; } +static int +nftnl_expr_bitwise_snprintf_bool(char *buf, size_t remain, const char *op, + const struct nftnl_expr *e, + const struct nftnl_expr_bitwise *bitwise) +{ + int offset = 0, ret; + + ret = snprintf(buf, remain, "reg %u = ( reg %u %s ", + bitwise->dreg, bitwise->sreg, op); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG2)) + ret = snprintf(buf + offset, remain, "reg %u ", bitwise->sreg2); + else + ret = nftnl_data_reg_snprintf(buf + offset, remain, + &bitwise->data, + 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(char *buf, size_t size, uint32_t flags, const struct nftnl_expr *e) @@ -252,10 +291,24 @@ nftnl_expr_bitwise_snprintf(char *buf, size_t size, err = nftnl_expr_bitwise_snprintf_mask_xor(buf, size, bitwise); break; case NFT_BITWISE_LSHIFT: - err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", bitwise); + err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", + bitwise); break; case NFT_BITWISE_RSHIFT: - err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", bitwise); + err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", + bitwise); + break; + case NFT_BITWISE_AND: + err = nftnl_expr_bitwise_snprintf_bool(buf, size, "&", e, + bitwise); + break; + case NFT_BITWISE_OR: + err = nftnl_expr_bitwise_snprintf_bool(buf, size, "|", e, + bitwise); + break; + case NFT_BITWISE_XOR: + err = nftnl_expr_bitwise_snprintf_bool(buf, size, "^", e, + bitwise); break; } -- cgit v1.2.3