mptcp: add MPTCP_TCPRST support

This adds the 'mp_reset' keyword to allow sending packets with TCPRST suboption.

Examples:
1.0 R. 1:1(0) ack 1001 win 264 <mp_reset 1>
1.0 R. 1:1(0) ack 1001 win 264 <mp_reset 1 flags [ flag_t ]>

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

gtests/net/packetdrill/lexer.l

@@ -246,6 +246,7 @@ flag_e return FLAG_E;
 flag_f return FLAG_F;
 flag_g return FLAG_G;
 flag_h return FLAG_H;
+flag_t return FLAG_T;
 no_flags return NO_FLAGS;
 nokey return NOKEY;
 mp_join_syn return MP_JOIN_SYN;
@@ -261,6 +262,7 @@ list_id return LIST_ID;
 mp_prio return MP_PRIO;
 mp_fail return MP_FAIL;
 mp_fastclose return MP_FASTCLOSE;
+mp_reset return MP_TCPRST;
 rand return RAND;
 sender_hmac return SENDER_HMAC;
 hmac return ADD_ADDR_HMAC;

gtests/net/packetdrill/mptcp.h

@@ -40,6 +40,7 @@
 #define MP_PRIO_SUBTYPE 5 // TODO, Change Subflow Priority
 #define MP_FAIL_SUBTYPE 6 // TODO
 #define MP_FASTCLOSE_SUBTYPE 7 // TODO => enhancement
+#define MP_TCPRST_SUBTYPE 8
 
 
 /* MPTCP options subtypes length */
@@ -86,6 +87,8 @@
 #define TCPOLEN_MP_FAIL 12
 // MP_FASTCLOSE
 #define TCPOLEN_MP_FASTCLOSE 12
+// MP_RESET
+#define TCPOLEN_MP_TCPRST 4
 // MPTCP Flags
 #define MP_CAPABLE_FLAGS 1
 #define MP_CAPABLE_FLAGS_CS 129 //With checksum
@@ -107,6 +110,8 @@
 
 #define MPTCP_VER_DEFAULT MPTCPV1
 
+#define MP_TCPRST_FLAG_T 1
+
 //SUBFLOW states
 #define ESTABLISHED 1 //for Subflow state
 #define PRE_ESTABLISHED 0 //Subflow state

gtests/net/packetdrill/parser.y

@@ -845,7 +845,7 @@ struct tcp_option *dss_do_dsn_dack( int dack_type, int dack_val,
 %token <reserved> U32 U64 PTR
 %token <reserved> ACK ECR EOL MSS NOP SACK SACKOK TIMESTAMP VAL WIN WSCALE
 %token <reserved> URG MD5 FAST_OPEN FAST_OPEN_EXP
-%token <reserved> MP_CAPABLE MP_CAPABLE_NO_CS MP_FASTCLOSE FLAG_A FLAG_B FLAG_C FLAG_D FLAG_E FLAG_F FLAG_G FLAG_H NO_FLAGS
+%token <reserved> MP_CAPABLE MP_CAPABLE_NO_CS MP_FASTCLOSE FLAG_A FLAG_B FLAG_C FLAG_D FLAG_E FLAG_F FLAG_G FLAG_H FLAG_T NO_FLAGS
 %token <reserved> MPCAPABLE V0 V1 NOKEY MPCDATALEN
 %token <reserved> MP_JOIN_SYN MP_JOIN_ACK MP_JOIN_SYN_ACK
 %token <reserved> DSS DACK4 DSN4 DACK8 DSN8 FIN SSN DLL NOCS CKSUM ADDR ADDRESS_ID BACKUP TOKEN AUTO RAND
@@ -854,6 +854,7 @@ struct tcp_option *dss_do_dsn_dack( int dack_type, int dack_val,
 %token <reserved> ADD_ADDRESS ADD_ADDR_IPV4 ADD_ADDR_IPV6 PORT MP_FAIL
 %token <reserved> REMOVE_ADDRESS ADDRESSES_ID LIST_ID
 %token <reserved> MP_PRIO
+%token <reserved> MP_TCPRST
 %token <reserved> TOS FLAGS FLOWLABEL
 %token <reserved> ECT0 ECT1 CE ECT01 NO_ECN
 %token <reserved> IPV4 IPV6 ICMP UDP RAW GRE MTU ID
@@ -883,6 +884,8 @@ struct tcp_option *dss_do_dsn_dack( int dack_type, int dack_val,
 %type <integer> opt_mpls_stack_bottom
 %type <integer> opt_icmp_mtu fin ssn dll dss_checksum
 %type <integer> mp_capable_no_cs is_backup address_id rand port
+%type <integer> mptcprst_reason mptcprst_flags_list mptcprst_flags mptcprst_flag
+
 %type <integer> flag_a flag_b flag_c flag_d flag_e flag_f flag_g flag_h no_flags
 %type <integer> mpc_ver mpc_flags_list mpc_flags mpc_flag mpc_keys mpc_data
 %type <integer> gre_flags_list gre_flags gre_flag
@@ -2048,6 +2051,27 @@ mpc_data
 }
 ;
 
+mptcprst_reason
+: INTEGER {
+ if(!is_valid_u8($1))
+ semantic_error("mp_reset: reason code should be a 8 bits unsigned integer.");
+ $$ = $1;
+}
+
+mptcprst_flags_list
+: FLAGS '[' mptcprst_flags ']' { $$ = $3; }
+| { $$ = 0; }
+;
+
+mptcprst_flags
+: mptcprst_flag { $$ = $1; }
+;
+
+mptcprst_flag
+: NO_FLAGS { $$ = 0; }
+| FLAG_T { $$ = MP_TCPRST_FLAG_T; }
+;
+
 tcp_option
 : NOP { $$ = tcp_option_new(TCPOPT_NOP, 1); }
 | EOL { $$ = tcp_option_new(TCPOPT_EOL, 1); }
@@ -2302,6 +2326,14 @@ tcp_option
  $$->data.mp_prio.flags = $2;
  $$->data.mp_capable.subtype = MP_PRIO_SUBTYPE;
 }
+| MP_TCPRST mptcprst_reason mptcprst_flags_list {
+ $$ = tcp_option_new(TCPOPT_MPTCP, TCPOLEN_MP_TCPRST);
+ $$->data.mp_tcprst.reason = $2;
+ $$->data.mp_tcprst.flag_transient = ($3 & MP_TCPRST_FLAG_T);
+ $$->data.mp_tcprst.reserved_bits = ZERO_RESERVED;
+
+ $$->data.mp_capable.subtype = MP_TCPRST_SUBTYPE;
+}
 | MP_FAIL dsn {
  if($2.type == 4)
  semantic_error("Value assigned to a MP_FAIL option is not a valid unsigned 64 bits number.");

gtests/net/packetdrill/run_packet.c

@@ -1237,6 +1237,14 @@ bool same_mptcp_opt(struct tcp_option *opt_a, struct tcp_option *opt_b, struct p
  if(opt_a->data.mp_fastclose.receiver_key != opt_b->data.mp_fastclose.receiver_key)
  return false;
  break;
+ case MP_TCPRST_SUBTYPE:
+ if(opt_a->data.mp_tcprst.reason != opt_b->data.mp_tcprst.reason)
+ return false;
+ if(opt_a->data.mp_tcprst.flag_transient != opt_b->data.mp_tcprst.flag_transient)
+ return false;
+ if(opt_a->data.mp_tcprst.reserved_bits != opt_b->data.mp_tcprst.reserved_bits)
+ return false;
+ break;
  default:
  return false;
  }

gtests/net/packetdrill/tcp_options.h

@@ -376,6 +376,25 @@ struct tcp_option {
  +---------------------------------------------------------------+
  */
  } __packed mp_fastclose;
+ struct {
+ #if __BYTE_ORDER == __LITTLE_ENDIAN
+ __u8 flag_transient:1, reserved_bits:3;
+ __u8 subtype:4;
+ __u8 reason;
+ #elif __BYTE_ORDER == __BIG_ENDIAN
+ __u8 subtype:4;
+ __u8 reserved_bits:3, flag_transient:1;
+ __u8 reason;
+ #else
+ #error "Adjust your <asm/byteorder.h> defines"
+ #endif
+ /*
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ +---------------+---------------+-------+-----------------------+
+ | Kind | Length |Subtype|U V W T| Reason |
+ +---------------+---------------+-------+-----------------------+
+ */
+ } __packed mp_tcprst;
  /*******END MPTCP options*********/
  } data;
 } __packed;

gtests/net/packetdrill/tcp_options_to_string.c

@@ -473,6 +473,11 @@ int tcp_options_to_string(struct packet *packet,
  fprintf(s, "mp_fastclose receiver key: %lu",
  (unsigned long)option->data.mp_fastclose.receiver_key);
  break;
+ case MP_TCPRST_SUBTYPE:
+ fprintf(s, "mp_reset %u", option->data.mp_tcprst.reason);
+ if (option->data.mp_tcprst.flag_transient)
+ fprintf(s, "flags [ flag_t ]");
+ break;
  default:
  fprintf(s, "unknown MPTCP subtype");
  break;