chiark / gitweb /
buffers: Introduce buf_remaining_space
[secnet.git] / tun.c
diff --git a/tun.c b/tun.c
index 63aa1f1..d4070f2 100644 (file)
--- a/tun.c
+++ b/tun.c
@@ -3,6 +3,7 @@
 #include "netlink.h"
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
@@ -68,22 +69,21 @@ static struct flagstr config_types[]={
 struct tun {
     struct netlink nl;
     int fd;
-    string_t device_path;
-    string_t ip_path;
+    cstring_t device_path;
+    cstring_t ip_path;
     string_t interface_name;
-    string_t ifconfig_path;
+    cstring_t ifconfig_path;
     uint32_t ifconfig_type;
-    string_t route_path;
+    cstring_t route_path;
     uint32_t route_type;
     uint32_t tun_flavour;
     bool_t search_for_if; /* Applies to tun-BSD only */
     struct buffer_if *buff; /* We receive packets into here
                               and send them to the netlink code. */
     netlink_deliver_fn *netlink_to_tunnel;
-    uint32_t local_address; /* host interface address */
 };
 
-static string_t tun_flavour_str(uint32_t flavour)
+static cstring_t tun_flavour_str(uint32_t flavour)
 {
     switch (flavour) {
     case TUN_FLAVOUR_GUESS: return "guess";
@@ -95,18 +95,16 @@ static string_t tun_flavour_str(uint32_t flavour)
 }
 
 static int tun_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
-                         int *timeout_io, const struct timeval *tv_now,
-                         uint64_t *now)
+                         int *timeout_io)
 {
     struct tun *st=sst;
     *nfds_io=1;
     fds[0].fd=st->fd;
-    fds[0].events=POLLIN|POLLERR|POLLHUP;
+    fds[0].events=POLLIN;
     return 0;
 }
 
-static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds,
-                           const struct timeval *tv_now, uint64_t *now)
+static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds)
 {
     struct tun *st=sst;
     int l;
@@ -117,13 +115,13 @@ static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds,
     }
     if (fds[0].revents&POLLIN) {
        BUF_ALLOC(st->buff,"tun_afterpoll");
-       buffer_init(st->buff,st->nl.max_start_pad);
-       l=read(st->fd,st->buff->start,st->buff->len-st->nl.max_start_pad);
+       buffer_init(st->buff,calculate_max_start_pad());
+       l=read(st->fd, st->buff->start, buf_remaining_space(st->buff));
        if (l<0) {
            fatal_perror("tun_afterpoll: read()");
        }
        if (l==0) {
-           fatal("tun_afterpoll: read()=0; device gone away?\n");
+           fatal("tun_afterpoll: read()=0; device gone away?");
        }
        if (l>0) {
            st->buff->size=l;
@@ -136,11 +134,27 @@ static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds,
 static void tun_deliver_to_kernel(void *sst, struct buffer_if *buf)
 {
     struct tun *st=sst;
+    ssize_t rc;
 
     BUF_ASSERT_USED(buf);
-    /* No error checking, because we'd just throw the packet away
-       anyway if it didn't work. */
-    write(st->fd,buf->start,buf->size);
+    
+    /* Log errors, so we can tell what's going on, but only once a
+       minute, so we don't flood the logs.  Short writes count as
+       errors. */
+    rc = write(st->fd,buf->start,buf->size);
+    if(rc != buf->size) {
+       static struct timeval last_report;
+       if(tv_now_global.tv_sec >= last_report.tv_sec + 60) {
+           if(rc < 0)
+               Message(M_WARNING,
+                       "failed to deliver packet to tun device: %s\n",
+                       strerror(errno));
+           else
+               Message(M_WARNING,
+                       "truncated packet delivered to tun device\n");
+           last_report = tv_now_global;
+       }
+    }
     BUF_FREE(buf);
 }
 
@@ -149,10 +163,16 @@ static bool_t tun_set_route(void *sst, struct netlink_client *routes)
     struct tun *st=sst;
     string_t network, mask, secnetaddr;
     struct subnet_list *nets;
-    uint32_t i;
+    int32_t i;
     int fd=-1;
+    bool_t up;
+
+    if (routes->options & OPT_SOFTROUTE)
+        up = routes->up;
+    else
+        up = routes->link_quality > LINK_QUALITY_UNUSED;
 
-    if (routes->up == routes->kup) return False;
+    if (up == routes->kup) return False;
     if (st->route_type==TUN_CONFIG_IOCTL) {
        if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
            fd=open(st->ip_path,O_RDWR);
@@ -172,30 +192,31 @@ static bool_t tun_set_route(void *sst, struct netlink_client *routes)
        network=ipaddr_to_string(nets->list[i].prefix);
        mask=ipaddr_to_string(nets->list[i].mask);
        Message(M_INFO,"%s: %s route %s/%d %s kernel routing table\n",
-               st->nl.name,routes->up?"adding":"deleting",network,
-               nets->list[i].len,routes->up?"to":"from");
+               st->nl.name,up?"adding":"deleting",network,
+               nets->list[i].len,up?"to":"from");
        switch (st->route_type) {
        case TUN_CONFIG_LINUX:
-           sys_cmd(st->route_path,"route",routes->up?"add":"del",
+           sys_cmd(st->route_path,"route",up?"add":"del",
                    "-net",network,"netmask",mask,
                    "gw",secnetaddr,(char *)0);
            break;
        case TUN_CONFIG_BSD:
-           sys_cmd(st->route_path,"route",routes->up?"add":"del",
+           sys_cmd(st->route_path,"route",up?"add":"del",
                    "-net",network,secnetaddr,mask,(char *)0);
            break;
        case TUN_CONFIG_SOLARIS25:
-           sys_cmd(st->route_path,"route",routes->up?"add":"del",
+           sys_cmd(st->route_path,"route",up?"add":"del",
                    network,secnetaddr,(char *)0);
            break;
        case TUN_CONFIG_IOCTL:
        {
-#ifdef HAVE_NET_ROUTE_H
+         /* darwin rtentry has a different format, use /sbin/route instead */
+#if HAVE_NET_ROUTE_H && ! __APPLE__
            struct rtentry rt;
            struct sockaddr_in *sa;
            int action;
            
-           memset(&rt,0,sizeof(rt));
+           FILLZERO(rt);
            sa=(struct sockaddr_in *)&rt.rt_dst;
            sa->sin_family=AF_INET;
            sa->sin_addr.s_addr=htonl(nets->list[i].prefix);
@@ -206,26 +227,24 @@ static bool_t tun_set_route(void *sst, struct netlink_client *routes)
            sa->sin_family=AF_INET;
            sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
            rt.rt_flags=RTF_UP|RTF_GATEWAY;
-           action=routes->up?SIOCADDRT:SIOCDELRT;
+           action=up?SIOCADDRT:SIOCDELRT;
            if (ioctl(fd,action,&rt)<0) {
                fatal_perror("tun_set_route: ioctl()");
            }
 #else
-           fatal("tun_set_route: ioctl method not supported\n");
+           fatal("tun_set_route: ioctl method not supported");
 #endif
        }
        break;
        default:
-           fatal("tun_set_route: unsupported route command type\n");
+           fatal("tun_set_route: unsupported route command type");
            break;
        }
-       free(network); free(mask);
     }
-    free(secnetaddr);
     if (st->route_type==TUN_CONFIG_IOCTL) {
        close(fd);
     }
-    routes->kup=routes->up;
+    routes->kup=up;
     return True;
 }
 
@@ -233,7 +252,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
 {
     struct tun *st=sst;
     string_t hostaddr,secnetaddr;
-    uint8_t mtu[6];
+    char mtu[6];
     struct netlink_client *r;
 
     if (st->tun_flavour==TUN_FLAVOUR_BSD) {
@@ -255,7 +274,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
                }
            }
            if (st->fd==-1) {
-               fatal("%s: unable to open any TUN device (%s...)\n",
+               fatal("%s: unable to open any TUN device (%s...)",
                      st->nl.name,st->device_path);
            }
        } else {
@@ -276,7 +295,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
            fatal_perror("%s: can't open device file %s",st->nl.name,
                         st->device_path);
        }
-       memset(&ifr,0,sizeof(ifr));
+       FILLZERO(ifr);
        ifr.ifr_flags = IFF_TUN | IFF_NO_PI; /* Just send/receive IP packets,
                                                no extra headers */
        if (st->interface_name)
@@ -291,7 +310,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
                    st->interface_name);
        }
 #else
-       fatal("tun_phase_hook: TUN_FLAVOUR_LINUX unexpected\n");
+       fatal("tun_phase_hook: TUN_FLAVOUR_LINUX unexpected");
 #endif /* LINUX_TUN_SUPPORTED */
     } else if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 #ifdef HAVE_TUN_STREAMS
@@ -322,21 +341,21 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
        sprintf(st->interface_name,"tun%d",ppa);
        st->fd=tun_fd;
 #else
-       fatal("tun_phase_hook: TUN_FLAVOUR_STREAMS unexpected\n");
+       fatal("tun_phase_hook: TUN_FLAVOUR_STREAMS unexpected");
 #endif /* HAVE_TUN_STREAMS */
     } else {
-       fatal("tun_phase_hook: unknown flavour of TUN\n");
+       fatal("tun_phase_hook: unknown flavour of TUN");
     }
     /* All the networks we'll be using have been registered. Invoke ifconfig
        to set the TUN device's address, and route to add routes to all
        our networks. */
 
-    hostaddr=ipaddr_to_string(st->local_address);
+    hostaddr=ipaddr_to_string(st->nl.local_address);
     secnetaddr=ipaddr_to_string(st->nl.secnet_address);
-    snprintf(mtu,6,"%d",st->nl.mtu);
+    snprintf(mtu,sizeof(mtu),"%d",st->nl.mtu);
     mtu[5]=0;
 
-    switch (st->route_type) {
+    switch (st->ifconfig_type) {
     case TUN_CONFIG_LINUX:
        sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
                hostaddr,"netmask","255.255.255.255","-broadcast",
@@ -353,7 +372,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
                hostaddr,secnetaddr,"mtu",mtu,"up",(char *)0);
        break;
     case TUN_CONFIG_IOCTL:
-#ifdef HAVE_NET_IF_H
+#if HAVE_NET_IF_H && ! __APPLE__
     {
        int fd;
        struct ifreq ifr;
@@ -363,9 +382,9 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
        /* Interface address */
        strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
        sa=(struct sockaddr_in *)&ifr.ifr_addr;
-       memset(sa,0,sizeof(*sa));
+       FILLZERO(*sa);
        sa->sin_family=AF_INET;
-       sa->sin_addr.s_addr=htonl(st->local_address);
+       sa->sin_addr.s_addr=htonl(st->nl.local_address);
        if (ioctl(fd,SIOCSIFADDR, &ifr)!=0) {
            fatal_perror("tun_apply: SIOCSIFADDR");
        }
@@ -373,7 +392,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
        /* Netmask */
        strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
        sa=(struct sockaddr_in *)&ifr.ifr_netmask;
-       memset(sa,0,sizeof(*sa));
+       FILLZERO(*sa);
        sa->sin_family=AF_INET;
        sa->sin_addr.s_addr=htonl(0xffffffff);
        if (ioctl(fd,SIOCSIFNETMASK, &ifr)!=0) {
@@ -383,7 +402,7 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
        /* Destination address (point-to-point) */
        strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
        sa=(struct sockaddr_in *)&ifr.ifr_dstaddr;
-       memset(sa,0,sizeof(*sa));
+       FILLZERO(*sa);
        sa->sin_family=AF_INET;
        sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
        if (ioctl(fd,SIOCSIFDSTADDR, &ifr)!=0) {
@@ -405,11 +424,11 @@ static void tun_phase_hook(void *sst, uint32_t newphase)
        close(fd);
     }
 #else
-    fatal("tun_apply: ifconfig by ioctl() not supported\n");
+    fatal("tun_apply: ifconfig by ioctl() not supported");
 #endif /* HAVE_NET_IF_H */
     break;
     default:
-       fatal("tun_apply: unsupported ifconfig method\n");
+       fatal("tun_apply: unsupported ifconfig method");
        break;
     }
        
@@ -469,8 +488,6 @@ static list_t *tun_create(closure_t *self, struct cloc loc, dict_t *context,
     st->route_path=dict_read_string(dict,"route-path",False,"tun-netlink",loc);
 
     st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"tun-netlink",loc);
-    st->local_address=string_item_to_ipaddr(
-       dict_find_item(dict,"local-address", True, "netlink", loc),"netlink");
 
     if (st->tun_flavour==TUN_FLAVOUR_GUESS) {
        /* If we haven't been told what type of TUN we're using, take
@@ -480,13 +497,11 @@ static list_t *tun_create(closure_t *self, struct cloc loc, dict_t *context,
            fatal_perror("tun_create: uname");
        }
        if (strcmp(u.sysname,"Linux")==0) {
-           if (u.release[0]=='2' && u.release[1]=='.' && u.release[3]=='.') {
-               if (u.release[2]=='2') st->tun_flavour=TUN_FLAVOUR_BSD;
-               else if (u.release[2]=='4') st->tun_flavour=TUN_FLAVOUR_LINUX;
-           }
+           st->tun_flavour=TUN_FLAVOUR_LINUX;
        } else if (strcmp(u.sysname,"SunOS")==0) {
            st->tun_flavour=TUN_FLAVOUR_STREAMS;
-       } else if (strcmp(u.sysname,"FreeBSD")==0) {
+       } else if (strcmp(u.sysname,"FreeBSD")==0
+                  || strcmp(u.sysname,"Darwin")==0) {
            st->tun_flavour=TUN_FLAVOUR_BSD;
        }
     }
@@ -501,7 +516,13 @@ static list_t *tun_create(closure_t *self, struct cloc loc, dict_t *context,
            st->ifconfig_type=TUN_CONFIG_IOCTL;
            break;
        case TUN_FLAVOUR_BSD:
+#if __linux__
+           /* XXX on Linux we still want TUN_CONFIG_IOCTL.  Perhaps we can
+              use this on BSD too. */
+           st->ifconfig_type=TUN_CONFIG_IOCTL;
+#else    
            st->ifconfig_type=TUN_CONFIG_BSD;
+#endif
            break;
        case TUN_FLAVOUR_STREAMS:
            st->ifconfig_type=TUN_CONFIG_BSD;
@@ -595,7 +616,6 @@ static list_t *tun_bsd_apply(closure_t *self, struct cloc loc, dict_t *context,
     return tun_create(self,loc,context,args,TUN_FLAVOUR_BSD);
 }
 
-init_module tun_module;
 void tun_module(dict_t *dict)
 {
     add_closure(dict,"tun",tun_apply);