diff options
Diffstat (limited to 'fw/src/ether.c')
| -rw-r--r-- | fw/src/ether.c | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/fw/src/ether.c b/fw/src/ether.c index dd20971..d77143a 100644 --- a/fw/src/ether.c +++ b/fw/src/ether.c @@ -38,7 +38,6 @@ enum Arplen = 28, Eminlen = 60, /* ethernet minimum frame, devether enforces it */ - Maxframe = Ehdrlen + 16*1024, Arpreq = 1, Arpreply = 2, @@ -321,19 +320,21 @@ etherisip(uchar *f, int n) * its ethernet address yet we ask and drop this one; the sender will * try again, which is what every other stack does too. */ +/* + * Build a frame around an IP packet and send it. The frame buffer + * belongs to the caller: 64K of it on the stack once overran a proc + * stack and corrupted the data segment, and sizing it here instead + * only moves the question of how big is big enough away from the one + * place - etherout - that knows how much it can read. + */ int -etherwriteip(uchar *p, int n, uchar *mask) +etherwriteip(uchar *f, int nf, uchar *p, int n, uchar *mask) { - /* - * On a proc stack, which libthread keeps small: 64K here - * overran it and corrupted the data segment. pktmedium's maxtu - * is 4096, so this is already generous. - */ - uchar f[Maxframe], dst[IPaddrlen], hop[IPaddrlen]; + uchar dst[IPaddrlen], hop[IPaddrlen]; uchar net[IPaddrlen], ournet[IPaddrlen], mac[Eaddrlen]; int type, len; - if(n < 20 || n > Maxframe - Ehdrlen) + if(n < 20 || nf < Eminlen || n + Ehdrlen > nf) return -1; switch(p[0] >> 4){ case 4: @@ -369,10 +370,13 @@ etherwriteip(uchar *p, int n, uchar *mask) if(!isv4(hop)){ static int said; - if(!said++) + if(!said++){ fprint(2, "fw: cannot resolve %I: " "IPv6 neighbour discovery is not implemented, " "so v6 unicast is dropped\n", hop); + syslog(0, "fw", "dropping v6 unicast to %I: " + "no neighbour discovery", hop); + } return -1; } if(etherdebug) |