From e21ce8c7c013fb223a002c70bb0a547de6c26c12 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Mon, 12 Sep 2005 14:27:37 -0700 Subject: [PATCH] [NETROM]: Implement G8PZT Circuit reset for NET/ROM NET/ROM is lacking a connection reset like TCP's RST flag which at times may result in a connecting having to slowly timing out instead of just being reset. An earlier attempt to reset the connection by sending a NR_CONNACK | NR_CHOKE_FLAG transport was inacceptable as it did result in crashes of BPQ systems. An alternative approach of introducing a new transport type 7 (NR_RESET) has be implemented several years ago in Paula Jayne Dowie G8PZT's Xrouter. Implement NR_RESET for Linux's NET/ROM but like any messing with the state engine consider this experimental for now and thus control it by a sysctl (net.netrom.reset) which for the time being defaults to off. Signed-off-by: Ralf Baechle DL5RB Signed-off-by: David S. Miller --- include/linux/sysctl.h | 3 ++- include/net/netrom.h | 27 ++++++++++++++++++++++++++- net/netrom/af_netrom.c | 21 +++++++++++---------- net/netrom/nr_in.c | 15 +++++++++++++++ net/netrom/nr_subr.c | 7 +++---- net/netrom/sysctl_net_netrom.c | 12 ++++++++++++ 6 files changed, 69 insertions(+), 16 deletions(-) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 532a6c5c24e9..3a29a9f9b451 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -544,7 +544,8 @@ enum { NET_NETROM_TRANSPORT_REQUESTED_WINDOW_SIZE=8, NET_NETROM_TRANSPORT_NO_ACTIVITY_TIMEOUT=9, NET_NETROM_ROUTING_CONTROL=10, - NET_NETROM_LINK_FAILS_COUNT=11 + NET_NETROM_LINK_FAILS_COUNT=11, + NET_NETROM_RESET=12 }; /* /proc/sys/net/ax25 */ diff --git a/include/net/netrom.h b/include/net/netrom.h index 45f2c7616d8b..ad05d7a3c55d 100644 --- a/include/net/netrom.h +++ b/include/net/netrom.h @@ -22,6 +22,7 @@ #define NR_DISCACK 0x04 #define NR_INFO 0x05 #define NR_INFOACK 0x06 +#define NR_RESET 0x07 #define NR_CHOKE_FLAG 0x80 #define NR_NAK_FLAG 0x40 @@ -51,6 +52,7 @@ enum { #define NR_DEFAULT_TTL 16 /* Default Time To Live - 16 */ #define NR_DEFAULT_ROUTING 1 /* Is routing enabled ? */ #define NR_DEFAULT_FAILS 2 /* Link fails until route fails */ +#define NR_DEFAULT_RESET 0 /* Sent / accept reset cmds? */ #define NR_MODULUS 256 #define NR_MAX_WINDOW_SIZE 127 /* Maximum Window Allowable - 127 */ @@ -176,6 +178,8 @@ extern int sysctl_netrom_transport_requested_window_size; extern int sysctl_netrom_transport_no_activity_timeout; extern int sysctl_netrom_routing_control; extern int sysctl_netrom_link_fails_count; +extern int sysctl_netrom_reset_circuit; + extern int nr_rx_frame(struct sk_buff *, struct net_device *); extern void nr_destroy_socket(struct sock *); @@ -218,7 +222,28 @@ extern void nr_requeue_frames(struct sock *); extern int nr_validate_nr(struct sock *, unsigned short); extern int nr_in_rx_window(struct sock *, unsigned short); extern void nr_write_internal(struct sock *, int); -extern void nr_transmit_refusal(struct sk_buff *, int); + +extern void __nr_transmit_reply(struct sk_buff *skb, int mine, + unsigned char cmdflags); + +/* + * This routine is called when a Connect Acknowledge with the Choke Flag + * set is needed to refuse a connection. + */ +#define nr_transmit_refusal(skb, mine) \ +do { \ + __nr_transmit_reply((skb), (mine), NR_CONNACK | NR_CHOKE_FLAG); \ +} while (0) + +/* + * This routine is called when we don't have a circuit matching an incoming + * NET/ROM packet. This is an G8PZT Xrouter extension. + */ +#define nr_transmit_reset(skb, mine) \ +do { \ + __nr_transmit_reply((skb), (mine), NR_RESET); \ +} while (0) + extern void nr_disconnect(struct sock *, int); /* nr_timer.c */ diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c index 02b1ab52dbbf..8c3d3a78481e 100644 --- a/net/netrom/af_netrom.c +++ b/net/netrom/af_netrom.c @@ -56,6 +56,7 @@ int sysctl_netrom_transport_requested_window_size = NR_DEFAULT_WINDOW; int sysctl_netrom_transport_no_activity_timeout = NR_DEFAULT_IDLE; int sysctl_netrom_routing_control = NR_DEFAULT_ROUTING; int sysctl_netrom_link_fails_count = NR_DEFAULT_FAILS; +int sysctl_netrom_reset_circuit = NR_DEFAULT_RESET; static unsigned short circuit = 0x101; @@ -908,17 +909,17 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev) if (frametype != NR_CONNREQ) { /* * Here it would be nice to be able to send a reset but - * NET/ROM doesn't have one. The following hack would - * have been a way to extend the protocol but apparently - * it kills BPQ boxes... :-( + * NET/ROM doesn't have one. We've tried to extend the protocol + * by sending NR_CONNACK | NR_CHOKE_FLAGS replies but that + * apparently kills BPQ boxes... :-( + * So now we try to follow the established behaviour of + * G8PZT's Xrouter which is sending packets with command type 7 + * as an extension of the protocol. */ -#if 0 - /* - * Never reply to a CONNACK/CHOKE. - */ - if (frametype != NR_CONNACK || flags != NR_CHOKE_FLAG) - nr_transmit_refusal(skb, 1); -#endif + if (sysctl_netrom_reset_circuit && + (frametype != NR_RESET || flags != 0)) + nr_transmit_reset(skb, 1); + return 0; } diff --git a/net/netrom/nr_in.c b/net/netrom/nr_in.c index 64b81a796907..004e8599b8fe 100644 --- a/net/netrom/nr_in.c +++ b/net/netrom/nr_in.c @@ -98,6 +98,11 @@ static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, nr_disconnect(sk, ECONNREFUSED); break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } @@ -124,6 +129,11 @@ static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, nr_disconnect(sk, 0); break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } @@ -254,6 +264,11 @@ static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype } break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } diff --git a/net/netrom/nr_subr.c b/net/netrom/nr_subr.c index 587bed2674bf..bcb9946b4f56 100644 --- a/net/netrom/nr_subr.c +++ b/net/netrom/nr_subr.c @@ -210,10 +210,9 @@ void nr_write_internal(struct sock *sk, int frametype) } /* - * This routine is called when a Connect Acknowledge with the Choke Flag - * set is needed to refuse a connection. + * This routine is called to send an error reply. */ -void nr_transmit_refusal(struct sk_buff *skb, int mine) +void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags) { struct sk_buff *skbn; unsigned char *dptr; @@ -254,7 +253,7 @@ void nr_transmit_refusal(struct sk_buff *skb, int mine) *dptr++ = 0; } - *dptr++ = NR_CONNACK | NR_CHOKE_FLAG; + *dptr++ = cmdflags; *dptr++ = 0; if (!nr_route_frame(skbn, NULL)) diff --git a/net/netrom/sysctl_net_netrom.c b/net/netrom/sysctl_net_netrom.c index c9ed50382ea7..6bb8dda849dc 100644 --- a/net/netrom/sysctl_net_netrom.c +++ b/net/netrom/sysctl_net_netrom.c @@ -30,6 +30,7 @@ static int min_idle[] = {0 * HZ}; static int max_idle[] = {65535 * HZ}; static int min_route[] = {0}, max_route[] = {1}; static int min_fails[] = {1}, max_fails[] = {10}; +static int min_reset[] = {0}, max_reset[] = {1}; static struct ctl_table_header *nr_table_header; @@ -155,6 +156,17 @@ static ctl_table nr_table[] = { .extra1 = &min_fails, .extra2 = &max_fails }, + { + .ctl_name = NET_NETROM_RESET, + .procname = "reset", + .data = &sysctl_netrom_reset_circuit, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &min_reset, + .extra2 = &max_reset + }, { .ctl_name = 0 } }; -- GitLab