We can't predict netlock state when pipex(4) related (*if_qstart)()
handlers called. This means we can't use netlock within pppac_qstart()
and pppx_if_qstart() handlers. But actually we can't avoid netlock only
when we call (*if_output)() in pipex(4) PPPOE output path.
Introduce `pipexoutq' mbuf(9) queue, and put PPPOE related mbufs within.
Do (*if_output)() calls within netisr handler with netlock held.
The netlock assertion is still kept within pppac_qstart(),
pppx_if_qstart() and underlay code because some per session data relies
on netlock. These assertions will be removed with following diffs.
I also want to use mbuf(9) queue for pppoe(4) input path and remove
existing serialization hack provided by kernel lock.
Index: sys/net/if.c
===================================================================
RCS file: /cvs/src/sys/net/if.c,v
retrieving revision 1.653
diff -u -p -r1.653 if.c
--- sys/net/if.c 7 Jun 2022 22:18:34 -0000 1.653
+++ sys/net/if.c 27 Jun 2022 12:53:37 -0000
@@ -914,6 +914,11 @@ if_netisr(void *unused)
if (n & (1 << NETISR_BRIDGE))
bridgeintr();
#endif
+#ifdef PIPEX
+ if (n & (1 << NETISR_PIPEX))
+ pipexintr();
+#endif
+
t |= n;
}
Index: sys/net/netisr.h
===================================================================
RCS file: /cvs/src/sys/net/netisr.h,v
retrieving revision 1.56
diff -u -p -r1.56 netisr.h
--- sys/net/netisr.h 28 Apr 2022 16:56:39 -0000 1.56
+++ sys/net/netisr.h 27 Jun 2022 12:53:37 -0000
@@ -45,6 +45,7 @@
#define NETISR_PFSYNC 5 /* for pfsync "immediate" tx */
#define NETISR_ARP 18 /* same as AF_LINK */
#define NETISR_IPV6 24 /* same as AF_INET6 */
+#define NETISR_PIPEX 27 /* for pipex processing */
#define NETISR_PPP 28 /* for PPP processing */
#define NETISR_BRIDGE 29 /* for bridge processing */
#define NETISR_SWITCH 31 /* for switch dataplane */
@@ -65,6 +66,7 @@ void pppintr(void);
void bridgeintr(void);
void switchintr(void);
void pfsyncintr(void);
+void pipexintr(void);
#define schednetisr(anisr)
\
do { \
Index: sys/net/pipex.c
===================================================================
RCS file: /cvs/src/sys/net/pipex.c,v
retrieving revision 1.141
diff -u -p -r1.141 pipex.c
--- sys/net/pipex.c 26 Jun 2022 22:51:58 -0000 1.141
+++ sys/net/pipex.c 27 Jun 2022 12:53:37 -0000
@@ -52,6 +52,7 @@
#include <net/route.h>
#include <net/ppp_defs.h>
#include <net/ppp-comp.h>
+#include <net/netisr.h>
#include "pf.h"
#if NPF > 0
@@ -106,6 +107,9 @@ struct radix_node_head *pipex_rd_head6 =
struct timeout pipex_timer_ch; /* callout timer context */
int pipex_prune = 1; /* [I] walk list every seconds */
+struct mbuf_queue pipexoutq = MBUF_QUEUE_INITIALIZER(
+ IFQ_MAXLEN, IPL_SOFTNET);
+
/* borrow an mbuf pkthdr field */
#define ph_ppp_proto ether_vtag
@@ -194,6 +198,46 @@ pipex_ioctl(void *ownersc, u_long cmd, c
}
/************************************************************************
+ * Software Interrupt Handler
+ ************************************************************************/
+
+void
+pipexintr(void)
+{
+ struct mbuf_list ml;
+ struct mbuf *m;
+ struct pipex_session *session;
+
+ NET_ASSERT_LOCKED();
+
+ mq_delist(&pipexoutq, &ml);
+
+ while ((m = ml_dequeue(&ml)) != NULL) {
+ struct ifnet *ifp;
+
+ session = m->m_pkthdr.ph_cookie;
+
+ ifp = if_get(session->proto.pppoe.over_ifidx);
+ if (ifp != NULL) {
+ struct pipex_pppoe_header *pppoe;
+ int len;
+
+ pppoe = mtod(m, struct pipex_pppoe_header *);
+ len = ntohs(pppoe->length);
+ ifp->if_output(ifp, m, &session->peer.sa, NULL);
+ counters_pkt(session->stat_counters, pxc_opackets,
+ pxc_obytes, len);
+ } else {
+ m_freem(m);
+ counters_inc(session->stat_counters, pxc_oerrors);
+ }
+ if_put(ifp);
+
+ pipex_rele_session(session);
+ }
+}
+
+/************************************************************************
* Session management functions
************************************************************************/
int
@@ -1259,7 +1303,6 @@ Static void
pipex_pppoe_output(struct mbuf *m0, struct pipex_session *session)
{
struct pipex_pppoe_header *pppoe;
- struct ifnet *ifp;
int len, padlen;
/* save length for pppoe header */
@@ -1286,18 +1329,15 @@ pipex_pppoe_output(struct mbuf *m0, stru
pppoe->length = htons(len);
m0->m_pkthdr.ph_ifidx = session->proto.pppoe.over_ifidx;
+ refcnt_take(&session->pxs_refcnt);
+ m0->m_pkthdr.ph_cookie = session;
m0->m_flags &= ~(M_BCAST|M_MCAST);
- ifp = if_get(session->proto.pppoe.over_ifidx);
- if (ifp != NULL) {
- ifp->if_output(ifp, m0, &session->peer.sa, NULL);
- counters_pkt(session->stat_counters, pxc_opackets,
- pxc_obytes, len);
- } else {
- m_freem(m0);
+ if (mq_enqueue(&pipexoutq, m0) != 0) {
counters_inc(session->stat_counters, pxc_oerrors);
- }
- if_put(ifp);
+ pipex_rele_session(session);
+ } else
+ schednetisr(NETISR_PIPEX);
}
#endif /* PIPEX_PPPOE */
