On Sun, Feb 16, 2014 at 05:59:57PM +0100, Florian Westphal wrote: > Patrick McHardy <kaber@xxxxxxxxx> wrote: > > Ok I misunderstood your initial problem statement. So basically what it > > should currently do: > > > > ct labels foo => test whether that bit is set > > ct labels == foo => test whether foo and only foo is set > > > > Ok I can see the problem :) > > > > The implicit op only selects FLAGCMP for EXPR_LIST (see > > expr_evaluate_relational()). That should probably be changed to take the > > base type into account. This also seems wrong for the ct state expression, > > we currently use equality if only one state is specified but use a flag > > comparison if multiple flags are specified. > > I hacked something up to also select FLAGCMP for bitmask type. > > $ nft --debug=netlink add rule filter output ct labels foo > ip filter output 0 0 > [ ct load labels => reg 1 ] > [ bitwise reg 1 = (reg=1 & 0x00000001 0x00000000 0x00000000 0x00000000 ) ^ 0x00000000 0x00000000 0x00000000 0x00000000 ] > [ cmp neq reg 1 0x00000001 0x00000000 0x00000000 0x00000000 ] > > looks better. Still not exactly the same though. > The cmp neq will cause it to match when the label is not set. > > I then tried again with vanilla master branch: > tcp flags syn counter packets 0 bytes 0 > tcp flags fin,syn counter packets 184 bytes 24880 > > So, same problem there: EXPR_LIST == cmp neq. Is that intentional? > It seems wrong to me, e.g. "tcp flags fin,syn" will match virtually all > tcp packets. > > Maybe netlink_gen_flagcmp() should generate NFT_CMP_GT i.e.: > [ bitwise reg 1 = (reg=1 & 0x00000012 ) ^ 0x00000000 ] > [ cmp gt reg 1 0x00000000 ] > > At least that would be what I would have expected :-} > > Am I wrong? It should actually generate a NEQ 0. Seems this was broken in commit aae836a7 (src: use libnftables). Try the attached patch please. > As a side note, experimenting a bit with tcp flags: > > add rule filter output tcp flags & (syn|ack) == (syn|ack) > > works fine with current master branch. But list shows > > "tcp flags & 18 == 18", i.e. no symbol translation. > > Shouldn't it restore the symbolic names? > I think this is the very same problem that I had with my connlabel > dabbling, so it would be nice if it could be solved in generic way. Most likely. Please see if the attached patch solves this. diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index 332383a..3e9a078 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -285,7 +285,6 @@ static void netlink_gen_flagcmp(struct netlink_linearize_ctx *ctx, netlink_gen_raw_data(zero, expr->right->byteorder, len, &nld); nft_rule_expr_set_u32(nle, NFT_EXPR_CMP_SREG, sreg); nft_rule_expr_set_u32(nle, NFT_EXPR_CMP_OP, NFT_CMP_NEQ); - netlink_gen_data(expr->right, &nld); nft_rule_expr_set(nle, NFT_EXPR_CMP_DATA, nld.value, nld.len); nft_rule_add_expr(ctx->nlr, nle); -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
