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PPP, PPPoS, renamed PPP_INPROC_MULTITHREADED to PPP_INPROC_IRQ_SAFE

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Follow-up of the #44565 bug fix, renamed the misnamed
PPP_INPROC_MULTITHREADED to PPP_INPROC_IRQ_SAFE because it is
IRQ safe but not thread safe.

Updated PPP documentation which now clearly state when and how
this feature can be used.
This commit is contained in:
Sylvain Rochet 2015-03-19 21:41:36 +01:00
parent 9eb900c448
commit ee752ab1ce
6 changed files with 68 additions and 79 deletions
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48
doc/ppp.txt
View File

@ -6,7 +6,7 @@ Table of Contents:
1 - Supported PPP protocols and features
2 - Raw API PPP example for all protocols
3 - PPPoS input path (raw API, thread safe API, TCPIP API)
3 - PPPoS input path (raw API, IRQ safe API, TCPIP API)
4 - Thread safe PPP API (PPPAPI)
5 - Upgrading from lwIP <= 1.4.x to lwIP >= 1.5.x
@ -298,32 +298,34 @@ ppp_free(ppp);
3 PPPoS input path (raw API, thread safe API, TCPIP API)
========================================================
3 PPPoS input path (raw API, IRQ safe API, TCPIP API)
=====================================================
PPPoS requires a serial I/O SIO port (see include/lwip/sio.h).
Received data on serial port should be sent to lwIP using the pppos_input() or
pppos_input_sys() functions.
Received data on serial port should be sent to lwIP using the pppos_input()
function or the pppos_input_sys() function.
If PPP_INPROC_MULTITHREADED is 0 (the default), pppos_input() is not thread safe
and then *MUST* only be called inside the lwIP context. You should use that if
you are calling pppos_input() from your main loop context when NO_SYS=1.
If NO_SYS is 1 and if PPP_INPROC_IRQ_SAFE is 0 (the default), pppos_input()
is not IRQ safe and then *MUST* only be called inside your main loop.
If PPP_INPROC_MULTITHREADED is 1, pppos_input() is thread safe and can be called
from a dedicated RX-thread or from interrupt context… *BUT* you should NEVER
call pppos_connect(), pppos_listen() and ppp_free() if pppos_input() can still
be running, doing this is NOT thread safe. You should also avoid calling
pppos_input() if PPPoS session is not started yet.
Whatever the NO_SYS value, if PPP_INPROC_IRQ_SAFE is 1, pppos_input() is IRQ
safe and can be safely called from an interrupt context, using that is going
to reduce your need of buffer if pppos_input() is called byte after byte in
your rx serial interrupt.
Using PPP_INPROC_MULTITHREADED is discouraged unless you really know what you
are doing, though it may greatly reduce your need of buffer if pppos_input() is
called byte after byte in your rx serial interrupt, your move ;-)
if NO_SYS is 0, the thread safe way outside an interrupt context is to use
the pppos_input_tcpip() function to pass input data to the lwIP core thread
using the TCPIP API. This is thread safe in all cases but you should avoid
passing data byte after byte because it uses heavy locking (mailbox) and it
allocates pbuf, better fill them !
if NO_SYS is 0 and if PPP_INPROC_IRQ_SAFE is 1, you may also use pppos_input()
from an RX thread, however pppos_input() is not thread safe by itself. You can
do that *BUT* you should NEVER call pppos_connect(), pppos_listen() and
ppp_free() if pppos_input() can still be running, doing this is NOT thread safe
at all. Using PPP_INPROC_IRQ_SAFE from an RX thread is discouraged unless you
really know what you are doing, your move ;-)
Anyway, if you are using an OS (NO_SYS=0) and if PPP_INPROC_MULTITHREADED is 0,
you can use the pppos_input_tcpip() function to pass input data to the lwIP
core thread. This is thread safe in all cases but you should avoid passing
data byte after byte because it uses heavy locking (mailbox) and it allocates
pbuf, better fill them !
/*
* Fonction to call for received data
@ -386,6 +388,10 @@ from previous lwIP version is pretty easy:
* PPP_INPROC_OWNTHREAD was broken by design and was removed, you have to create
your own serial rx thread
* PPP_INPROC_MULTITHREADED option was misnamed and confusing and was renamed
PPP_INPROC_IRQ_SAFE, please read the "PPPoS input path" documentation above
because you might have been fooled by that
* If you used tcpip_callback_with_block() on ppp_ functions you may wish to use
the PPPAPI API instead.

8
src/api/tcpip.c
View File

@ -127,12 +127,12 @@ tcpip_thread(void *arg)
break;
#endif /* LWIP_TCPIP_CORE_LOCKING_INPUT */
#if PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED
#if PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE
case TCPIP_MSG_INPKT_PPPOS:
pppos_input_sys(msg->msg.inp.p, msg->msg.inp.netif);
memp_free(MEMP_TCPIP_MSG_INPKT, msg);
break;
#endif /* PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED */
#endif /* PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE */
#if LWIP_NETIF_API
case TCPIP_MSG_NETIFAPI:
@ -232,7 +232,7 @@ tcpip_input(struct pbuf *p, struct netif *inp)
#endif /* LWIP_TCPIP_CORE_LOCKING_INPUT */
}
#if PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED
#if PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE
/**
* Pass a received packet to tcpip_thread for input processing
*
@ -272,7 +272,7 @@ tcpip_pppos_input(struct pbuf *p, struct netif *inp)
return ERR_OK;
#endif /* LWIP_TCPIP_CORE_LOCKING_INPUT */
}
#endif /* PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED */
#endif /* PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE */
/**
* Call a specific function in the thread context of

18
src/include/lwip/opt.h
View File

@ -1916,22 +1916,12 @@
#if PPP_SUPPORT
/**
* PPP_INPROC_MULTITHREADED==1 call ppp_input() using tcpip_callback().
* PPP_INPROC_IRQ_SAFE==1 call pppos_input() using tcpip_callback().
*
* Set this to 0 in the following cases:
* - pppos_input() is called from the main loop and NO_SYS==1
* - you are using tcpip_input() (NO_SYS==0) on PPP data input
*
* Otherwise, if pppos_input() is called outside lwIP context (IRQ)
* set this to 1.
*
* CAUTION: if set to 1, you should NEVER call pppos_connect(), pppos_listen()
* and ppp_free() if pppos_input() can still be running, doing this is not
* thread safe. You should also avoid calling pppos_input() if PPPoS session
* is not started yet.
* Please read the "PPPoS input path" chapter in the PPP documentation about this option.
*/
#ifndef PPP_INPROC_MULTITHREADED
#define PPP_INPROC_MULTITHREADED 0
#ifndef PPP_INPROC_IRQ_SAFE
#define PPP_INPROC_IRQ_SAFE 0
#endif
/**

8
src/include/lwip/tcpip.h
View File

@ -143,9 +143,9 @@ err_t tcpip_apimsg(struct api_msg *apimsg);
err_t tcpip_input(struct pbuf *p, struct netif *inp);
#if PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED
#if PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE
err_t tcpip_pppos_input(struct pbuf *p, struct netif *inp);
#endif /* PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED */
#endif /* PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE */
#if LWIP_NETIF_API
err_t tcpip_netifapi(struct netifapi_msg *netifapimsg);
@ -182,9 +182,9 @@ enum tcpip_msg_type {
TCPIP_MSG_API,
#endif /* LWIP_NETCONN || LWIP_SOCKET */
TCPIP_MSG_INPKT,
#if PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED
#if PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE
TCPIP_MSG_INPKT_PPPOS,
#endif /* PPPOS_SUPPORT && !PPP_INPROC_MULTITHREADED */
#endif /* PPPOS_SUPPORT && !PPP_INPROC_IRQ_SAFE */
#if LWIP_NETIF_API
TCPIP_MSG_NETIFAPI,
#endif /* LWIP_NETIF_API */

8
src/include/netif/ppp/pppos.h
View File

@ -104,10 +104,10 @@ struct pppos_pcb_s {
ppp_pcb *pppos_create(struct netif *pppif, sio_fd_t fd,
ppp_link_status_cb_fn link_status_cb, void *ctx_cb);
#if !NO_SYS && !PPP_INPROC_MULTITHREADED
#if !NO_SYS && !PPP_INPROC_IRQ_SAFE
/* Pass received raw characters to PPPoS to be decoded through lwIP TCPIP thread. */
err_t pppos_input_tcpip(ppp_pcb *ppp, u8_t *s, int l);
#endif /* !NO_SYS && !PPP_INPROC_MULTITHREADED */
#endif /* !NO_SYS && !PPP_INPROC_IRQ_SAFE */
/* PPP over Serial: this is the input function to be called for received data. */
void pppos_input(ppp_pcb *ppp, u8_t* data, int len);
@ -117,9 +117,9 @@ void pppos_input(ppp_pcb *ppp, u8_t* data, int len);
* Functions called from lwIP
* DO NOT CALL FROM lwIP USER APPLICATION.
*/
#if !NO_SYS && !PPP_INPROC_MULTITHREADED
#if !NO_SYS && !PPP_INPROC_IRQ_SAFE
err_t pppos_input_sys(struct pbuf *p, struct netif *inp);
#endif /* !NO_SYS && !PPP_INPROC_MULTITHREADED */
#endif /* !NO_SYS && !PPP_INPROC_IRQ_SAFE */
#endif /* PPPOS_H */
#endif /* PPP_SUPPORT && PPPOL2TP_SUPPORT */

57
src/netif/ppp/pppos.c
View File

@ -70,9 +70,9 @@ static err_t pppos_netif_input(ppp_pcb *ppp, void *ctx, struct pbuf *p, u16_t pr
#endif /* VJ_SUPPORT */
/* Prototypes for procedures local to this file. */
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
static void pppos_input_callback(void *arg);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
static void pppos_input_free_current_packet(pppos_pcb *pppos);
static void pppos_input_drop(pppos_pcb *pppos);
static err_t pppos_output_append(pppos_pcb *pppos, err_t err, struct pbuf *nb, u8_t c, u8_t accm, u16_t *fcs);
@ -167,7 +167,7 @@ ppp_get_fcs(u8_t byte)
#define PPP_INITFCS 0xffff /* Initial FCS value */
#define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
#define PPPOS_DECL_PROTECT(lev) SYS_ARCH_DECL_PROTECT(lev)
#define PPPOS_PROTECT(lev) SYS_ARCH_PROTECT(lev)
#define PPPOS_UNPROTECT(lev) SYS_ARCH_UNPROTECT(lev)
@ -175,7 +175,7 @@ ppp_get_fcs(u8_t byte)
#define PPPOS_DECL_PROTECT(lev)
#define PPPOS_PROTECT(lev)
#define PPPOS_UNPROTECT(lev)
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
/*
@ -340,10 +340,10 @@ pppos_connect(ppp_pcb *ppp, void *ctx)
{
pppos_pcb *pppos = (pppos_pcb *)ctx;
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
/* input pbuf left over from last session? */
pppos_input_free_current_packet(pppos);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
ppp_clear(ppp);
/* reset PPPoS control block to its initial state */
@ -379,10 +379,10 @@ pppos_listen(ppp_pcb *ppp, void *ctx, struct ppp_addrs *addrs)
#endif /* PPP_IPV4_SUPPORT */
lcp_options *lcp_wo;
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
/* input pbuf left over from last session? */
pppos_input_free_current_packet(pppos);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
ppp_clear(ppp);
/* reset PPPoS control block to its initial state */
@ -442,14 +442,14 @@ pppos_disconnect(ppp_pcb *ppp, void *ctx)
pppos->open = 0;
PPPOS_UNPROTECT(lev);
/* If PPP_INPROC_MULTITHREADED is used we cannot call
/* If PPP_INPROC_IRQ_SAFE is used we cannot call
* pppos_input_free_current_packet() here because
* rx thread might still call pppos_input().
* rx IRQ might still call pppos_input().
*/
#if !PPP_INPROC_MULTITHREADED
#if !PPP_INPROC_IRQ_SAFE
/* input pbuf left ? */
pppos_input_free_current_packet(pppos);
#endif /* !PPP_INPROC_MULTITHREADED */
#endif /* !PPP_INPROC_IRQ_SAFE */
ppp_link_end(ppp); /* notify upper layers */
}
@ -460,16 +460,16 @@ pppos_destroy(ppp_pcb *ppp, void *ctx)
pppos_pcb *pppos = (pppos_pcb *)ctx;
LWIP_UNUSED_ARG(ppp);
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
/* input pbuf left ? */
pppos_input_free_current_packet(pppos);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
memp_free(MEMP_PPPOS_PCB, pppos);
return ERR_OK;
}
#if !NO_SYS && !PPP_INPROC_MULTITHREADED
#if !NO_SYS && !PPP_INPROC_IRQ_SAFE
/** Pass received raw characters to PPPoS to be decoded through lwIP TCPIP thread.
*
* @param pcb PPP descriptor index, returned by pppos_create()
@ -506,11 +506,11 @@ err_t pppos_input_sys(struct pbuf *p, struct netif *inp) {
pbuf_free(p);
return ERR_OK;
}
#endif /* !NO_SYS && !PPP_INPROC_MULTITHREADED */
#endif /* !NO_SYS && !PPP_INPROC_IRQ_SAFE */
/** PPPoS input helper struct, must be packed since it is stored
* to pbuf->payload, which might be unaligned. */
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
@ -522,16 +522,9 @@ PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
/** Pass received raw characters to PPPoS to be decoded.
*
* This function is thread-safe if PPP_INPROC_MULTITHREADED is set to 1
* and can be called from a dedicated RX-thread or from interrupt context
* BUT you should NEVER call pppos_connect(), pppos_listen()
* and ppp_free() if pppos_input() can still be running, doing this is not
* thread safe. You should also avoid calling pppos_input() if PPPoS session
* is not started yet.
*
* @param pcb PPP descriptor index, returned by pppos_create()
* @param data received data
@ -618,16 +611,16 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
/* hide the room for Ethernet forwarding header */
pbuf_header(inp, -(s16_t)PBUF_LINK_HLEN);
#endif /* IP_FORWARD || LWIP_IPV6_FORWARD */
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
if(tcpip_callback_with_block(pppos_input_callback, inp, 0) != ERR_OK) {
PPPDEBUG(LOG_ERR, ("pppos_input[%d]: tcpip_callback() failed, dropping packet\n", ppp->netif->num));
pbuf_free(inp);
LINK_STATS_INC(link.drop);
snmp_inc_ifindiscards(ppp->netif);
}
#else /* PPP_INPROC_MULTITHREADED */
#else /* PPP_INPROC_IRQ_SAFE */
ppp_input(ppp, inp);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
}
/* Prepare for a new packet. */
@ -740,11 +733,11 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
}
if (pppos->in_head == NULL) {
u8_t *payload = ((u8_t*)next_pbuf->payload) + pbuf_alloc_len;
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
((struct pppos_input_header*)payload)->ppp = ppp;
payload += sizeof(struct pppos_input_header);
next_pbuf->len += sizeof(struct pppos_input_header);
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
next_pbuf->len += sizeof(pppos->in_protocol);
*(payload++) = pppos->in_protocol >> 8;
*(payload) = pppos->in_protocol & 0xFF;
@ -767,7 +760,7 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
magic_randomize();
}
#if PPP_INPROC_MULTITHREADED
#if PPP_INPROC_IRQ_SAFE
/* PPPoS input callback using one input pointer
*/
static void pppos_input_callback(void *arg) {
@ -789,7 +782,7 @@ drop:
snmp_inc_ifindiscards(ppp->netif);
pbuf_free(pb);
}
#endif /* PPP_INPROC_MULTITHREADED */
#endif /* PPP_INPROC_IRQ_SAFE */
static void
pppos_send_config(ppp_pcb *ppp, void *ctx, u32_t accm, int pcomp, int accomp)