From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 21 Sep 2014 11:05:28 +0000 (+0100)
Subject: comm: Break out common code in comm
X-Git-Tag: proposed.polypath.v3~39
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;ds=sidebyside;h=db9d6ee0e906a4fa70e380dc79d158cd3dfec3fe;p=secnet.git

comm: Break out common code in comm

We are going to want to introduce a new kind of comm.  Currently we
only have one comm, udp, in udp.c - much of whose code we will want to
reuse.

Break that generic comm-handling code out into new files, functions
and macros.

No functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/Makefile.in b/Makefile.in
index 8a626ca..fb64c47 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -55,6 +55,7 @@ TARGETS:=secnet
 
 OBJECTS:=secnet.o util.o conffile.yy.o conffile.tab.o conffile.o modules.o \
 	resolver.o random.o udp.o site.o transform-cbcmac.o transform-eax.o \
+	comm-common.o \
 	netlink.o rsa.o dh.o serpent.o serpentbe.o \
 	md5.o sha512.o tun.o slip.o sha1.o ipaddr.o log.o \
 	process.o @LIBOBJS@ \
diff --git a/comm-common.c b/comm-common.c
new file mode 100644
index 0000000..476cba0
--- /dev/null
+++ b/comm-common.c
@@ -0,0 +1,55 @@
+
+#include "secnet.h"
+#include "comm-common.h"
+
+void comm_request_notify(void *commst, void *nst, comm_notify_fn *fn)
+{
+    struct commcommon *st=commst;
+    struct comm_notify_entry *n;
+    
+    n=safe_malloc(sizeof(*n),"comm_request_notify_core");
+    n->fn=fn;
+    n->state=nst;
+    n->fn=fn;
+    n->state=nst;
+    LIST_INSERT_HEAD(&st->notify, n, entry);
+}
+
+void comm_release_notify(void *commst, void *nst, comm_notify_fn *fn)
+{
+    struct commcommon *st=commst;
+    struct comm_notify_entry *n, *t;
+
+    /* XXX untested */
+    LIST_FOREACH_SAFE(n, &st->notify, entry, t) {
+       if (n->state==nst && n->fn==fn) {
+           LIST_REMOVE(n, entry);
+           free(n);
+       }
+    }
+}
+
+bool_t comm_notify(struct comm_notify_list *notify,
+		   struct buffer_if *buf, const struct comm_addr *ca)
+{
+    struct comm_notify_entry *n;
+
+    LIST_FOREACH(n, notify, entry) {
+	if (n->fn(n->state, buf, ca)) {
+	    return True;
+	}
+    }
+    return False;
+}
+
+void comm_apply(struct commcommon *cc)
+{
+    cc->cl.type=CL_COMM;
+    cc->cl.apply=NULL;
+    cc->cl.interface=&cc->ops;
+    cc->ops.st=cc;
+    cc->ops.request_notify=comm_request_notify;
+    cc->ops.release_notify=comm_release_notify;
+    LIST_INIT(&cc->notify);
+    cc->rbuf=NULL;
+}
diff --git a/comm-common.h b/comm-common.h
new file mode 100644
index 0000000..2c2d26a
--- /dev/null
+++ b/comm-common.h
@@ -0,0 +1,50 @@
+
+#ifndef COMM_COMMON_H
+#define COMM_COMMON_H
+
+#include "secnet.h"
+
+struct comm_notify_entry {
+    comm_notify_fn *fn;
+    void *state;
+    LIST_ENTRY(comm_notify_entry) entry;
+};
+LIST_HEAD(comm_notify_list, comm_notify_entry) notify;
+
+struct commcommon { /* must be first so that void* is comm_common* */
+    closure_t cl;
+    struct comm_if ops;
+    struct cloc loc;
+    struct comm_notify_list notify;
+    struct buffer_if *rbuf;
+};
+
+void comm_request_notify(void *commst, void *nst, comm_notify_fn *fn);
+void comm_release_notify(void *commst, void *nst, comm_notify_fn *fn);
+
+bool_t comm_notify(struct comm_notify_list *notify, struct buffer_if *buf,
+		   const struct comm_addr *ca);
+  /* Either: returns True, with message delivered and buffer freed.
+   * Or: False, if no-one wanted it - buffer still allocd'd.
+   * Ie, like comm_notify_fn. */
+
+void comm_apply(struct commcommon *cc);
+
+#define COMM_APPLY(st,cc,prefix,desc,loc)		\
+    (st)=safe_malloc(sizeof(*(st)), desc "_apply");	\
+    (cc)->loc=loc;					\
+    (cc)->cl.description=desc;				\
+    (cc)->ops.sendmsg=prefix##sendmsg;			\
+    (cc)->ops.addr_to_string=prefix##addr_to_string;	\
+    comm_apply((cc))
+   /* Expects in scope: prefix##sendmsg, prefix##addr_to_string. */
+
+#define COMM_APPLY_STANDARD(st,cc,desc,args)				\
+    item_t *item=list_elem(args,0);					\
+    if (!item || item->type!=t_dict) {					\
+	cfgfatal((cc)->loc,desc,"first argument must be a dictionary\n"); \
+    }									\
+    dict_t *d=item->data.dict;						\
+    (cc)->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,desc,(cc)->loc)
+
+#endif /*COMM_COMMON_H*/
diff --git a/secnet.h b/secnet.h
index 9ddd69d..3bd6159 100644
--- a/secnet.h
+++ b/secnet.h
@@ -378,7 +378,7 @@ struct comm_addr {
 };
 
 /* Return True if the packet was processed, and shouldn't be passed to
-   any other potential receivers. */
+   any other potential receivers. (buf is freed iff True returned.) */
 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 			      const struct comm_addr *source);
 typedef void comm_request_notify_fn(void *commst, void *nst,
diff --git a/udp.c b/udp.c
index dc98782..8bfa9a9 100644
--- a/udp.c
+++ b/udp.c
@@ -23,20 +23,12 @@
 #include "unaligned.h"
 #include "ipaddr.h"
 #include "magic.h"
+#include "comm-common.h"
 
 static beforepoll_fn udp_beforepoll;
 static afterpoll_fn udp_afterpoll;
-static comm_request_notify_fn request_notify;
-static comm_release_notify_fn release_notify;
 static comm_sendmsg_fn udp_sendmsg;
 
-struct comm_notify_entry {
-    comm_notify_fn *fn;
-    void *state;
-    LIST_ENTRY(comm_notify_entry) entry;
-};
-LIST_HEAD(comm_notify_list, comm_notify_entry) notify;
-
 #define UDP_MAX_SOCKETS 3 /* 2 ought to do really */
 
 struct udpsock {
@@ -45,19 +37,16 @@ struct udpsock {
 };
 
 struct udp {
-    closure_t cl;
-    struct comm_if ops;
-    struct cloc loc;
+    struct commcommon cc;
     int n_socks;
     struct udpsock socks[UDP_MAX_SOCKETS];
     string_t authbind;
-    struct buffer_if *rbuf;
-    struct comm_notify_list notify;
     bool_t use_proxy;
     union iaddr proxy;
 };
 
-static const char *addr_to_string(void *commst, const struct comm_addr *ca) {
+static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca)
+{
     struct udp *st=commst;
     struct udp *socks=st; /* for now */
     static char sbuf[100];
@@ -88,12 +77,11 @@ static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
 static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
 {
     struct udp *st=state;
+    struct commcommon *cc=&st->cc;
     struct udp *socks=st; /* for now */
-    struct udp *cc=st; /* for now */
     struct udp *uc=st; /* for now */
     union iaddr from;
     socklen_t fromlen;
-    struct comm_notify_entry *n;
     bool_t done;
     int rv;
     int i;
@@ -136,13 +124,7 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
 		ca.comm=&cc->ops;
 		ca.ia=from;
 		ca.ix=i;
-		done=False;
-		LIST_FOREACH(n, &cc->notify, entry) {
-		    if (n->fn(n->state, cc->rbuf, &ca)) {
-			done=True;
-			break;
-		    }
-		}
+		done=comm_notify(&cc->notify, cc->rbuf, &ca);
 		if (!done) {
 		    uint32_t msgtype;
 		    if (cc->rbuf->size>12 /* prevents traffic amplification */
@@ -164,33 +146,6 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
     }
 }
 
-static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
-{
-    struct udp *st=commst;
-    struct udp *cc=st; /* for now */
-    struct comm_notify_entry *n;
-    
-    n=safe_malloc(sizeof(*n),"request_notify");
-    n->fn=fn;
-    n->state=nst;
-    LIST_INSERT_HEAD(&cc->notify, n, entry);
-}
-
-static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
-{
-    struct udp *st=commst;
-    struct udp *cc=st; /* for now */
-    struct comm_notify_entry *n, *t;
-
-    /* XXX untested */
-    LIST_FOREACH_SAFE(n, &cc->notify, entry, t) {
-	if (n->state==nst && n->fn==fn) {
-	    LIST_REMOVE(n, entry);
-	    free(n);
-	}
-    }
-}
-
 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
 			  const struct comm_addr *dest)
 {
@@ -236,7 +191,7 @@ static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
 static void udp_make_socket(struct udp *st, struct udpsock *us)
 {
     const union iaddr *addr=&us->addr;
-    struct udp *cc=st; /* for now */
+    struct commcommon *cc=&st->cc; /* for now */
     struct udp *uc=st; /* for now */
     us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
     if (us->fd<0) {
@@ -343,22 +298,11 @@ static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
     uint32_t a;
     int i;
 
-    st=safe_malloc(sizeof(*st),"udp_apply(st)");
-    struct udp *cc=st; /* for now */
+    COMM_APPLY(st,&st->cc,udp_,"udp",loc);
+    struct commcommon *cc=&st->cc; /* for now */
     struct udp *uc=st; /* for now */
     struct udp *socks=st; /* for now */
-    cc->loc=loc;
-    cc->cl.description="udp";
-    cc->cl.type=CL_COMM;
-    cc->cl.apply=NULL;
-    cc->cl.interface=&cc->ops;
-    cc->ops.st=st;
-    cc->ops.request_notify=request_notify;
-    cc->ops.release_notify=release_notify;
-    cc->ops.sendmsg=udp_sendmsg;
-    cc->ops.addr_to_string=addr_to_string;
     uc->use_proxy=False;
-    LIST_INIT(&cc->notify);
 
     item=list_elem(args,0);
     if (!item || item->type!=t_dict) {