mptcp: add subtype matching

MPTCP multiplexes the various mptcp signalling data using the
first 4 bits of the mptcp option.

This allows to match on the mptcp subtype via:

   tcp option mptcp subtype 1

This misses delinearization support. mptcp subtype is the first tcp
option field that has a length of less than one byte.

Serialization processing will add a binop for this, but netlink
delinearization can't remove them, yet.

Also misses a new datatype/symbol table to allow to use mnemonics like
'mp_join' instead of raw numbers.

For this reason, no tests are added yet.

Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/include/tcpopt.h b/include/tcpopt.h
index 22df69dc5b93dd453c608a17e5cbc47cc44172a4..bb5c1329018e45559804f3b15b6fb86525aad2de 100644 (file)
--- a/include/tcpopt.h
+++ b/include/tcpopt.h
@@ -77,6 +77,7 @@ enum tcpopt_hdr_field_sack {
 enum tcpopt_hdr_mptcp_common {
        TCPOPT_MPTCP_KIND,
        TCPOPT_MPTCP_LENGTH,
+       TCPOPT_MPTCP_SUBTYPE,
 };
 
 extern const struct exthdr_desc *tcpopt_protocols[__TCPOPT_KIND_MAX];

diff --git a/src/parser_bison.y b/src/parser_bison.y
index a6a591b7e00dd70786f5099f2e00069f32e5bd8f..355758e1befb2e25dc9e4fe147ab3d1469557ac4 100644 (file)
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -424,6 +424,7 @@ int nft_lex(void *, void *, void *);
 %token RIGHT                   "right"
 %token TSVAL                   "tsval"
 %token TSECR                   "tsecr"
+%token SUBTYPE                 "subtype"
 
 %token DCCP                    "dccp"
 
@@ -882,7 +883,7 @@ int nft_lex(void *, void *, void *);
 %type <val>                    tcp_hdr_field
 %type <val>                    tcp_hdr_option_type
 %type <val>                    tcp_hdr_option_sack
-%type <val>                    tcpopt_field_maxseg     tcpopt_field_sack        tcpopt_field_tsopt     tcpopt_field_window
+%type <val>                    tcpopt_field_maxseg     tcpopt_field_mptcp      tcpopt_field_sack        tcpopt_field_tsopt     tcpopt_field_window
 %type <tcp_kind_field>         tcp_hdr_option_kind_and_field
 
 %type <expr>                   boolean_expr
@@ -5540,6 +5541,11 @@ tcp_hdr_option_kind_and_field    :       MSS     tcpopt_field_maxseg
                                        struct tcp_kind_field kind_field = { .kind = $1, .field = TCPOPT_COMMON_LENGTH };
                                        $$ = kind_field;
                                }
+                               |       MPTCP   tcpopt_field_mptcp
+                               {
+                                       struct tcp_kind_field kind_field = { .kind = TCPOPT_KIND_MPTCP, .field = $2 };
+                                       $$ = kind_field;
+                               }
                                ;
 
 tcp_hdr_option_sack    :       SACK            { $$ = TCPOPT_KIND_SACK; }
@@ -5583,6 +5589,9 @@ tcpopt_field_tsopt        :       TSVAL           { $$ = TCPOPT_TS_TSVAL; }
 tcpopt_field_maxseg    :       SIZE            { $$ = TCPOPT_MAXSEG_SIZE; }
                        ;
 
+tcpopt_field_mptcp     :       SUBTYPE         { $$ = TCPOPT_MPTCP_SUBTYPE; }
+                       ;
+
 dccp_hdr_expr          :       DCCP    dccp_hdr_field
                        {
                                $$ = payload_expr_alloc(&@$, &proto_dccp, $2);

diff --git a/src/scanner.l b/src/scanner.l
index c65d57846c5987903fbd6f41875e4287356c024d..f28bf3153f0b0090c139a341fde41161976edc11 100644 (file)
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -472,6 +472,7 @@ addrstring  ({macaddr}|{ip4addr}|{ip6addr})
 "fastopen"             { return FASTOPEN; }
 "mptcp"                        { return MPTCP; }
 "md5sig"               { return MD5SIG; }
+"subtype"              { return SUBTYPE; }
 "nop"                  { return NOP; }
 "noop"                 { return NOP; }
 "sack"                 { return SACK; }

diff --git a/src/tcpopt.c b/src/tcpopt.c
index 5913cd065d03c14c4df18d3fbe2c47df2de5b2f4..641daa7359a305f72b792feaf32cc031270ec994 100644 (file)
--- a/src/tcpopt.c
+++ b/src/tcpopt.c
@@ -116,6 +116,7 @@ static const struct exthdr_desc tcpopt_mptcp = {
        .templates      = {
                [TCPOPT_MPTCP_KIND]     = PHT("kind",   0,   8),
                [TCPOPT_MPTCP_LENGTH]   = PHT("length", 8,  8),
+               [TCPOPT_MPTCP_SUBTYPE]  = PHT("subtype", 16, 4),
        },
 };
 #undef PHT