From 8379ada798138cf6a8a29913ee1413bbde47e0e4 Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Mon, 25 Oct 1999 16:09:45 +0000 Subject: Patch from Eric Norum to address the following problem report from Philip A. Prindeville : I was working on a device driver for a certain ethernet chipset that occassionally wraps in its buffer, and causes a resulting mbuf chain with only a few dozen bytes in the first mbuf of the chain. I wouldn't have thought this would be a problem, until I ran some stress tests that flooded the ethernet receiver with packets and started to get panics here: 250 251 if (m->m_pkthdr.len < sizeof(struct ip)) 252 goto tooshort; 253 254 #ifdef DIAGNOSTIC 255 if (m->m_len < sizeof(struct ip)) 256 panic("ipintr mbuf too short"); 257 #endif 258 259 if (m->m_len < sizeof (struct ip) && 260 (m = m_pullup(m, sizeof (struct ip))) == 0) { 261 ipstat.ips_toosmall++; 262 return; 263 } 264 ip = mtod(m, struct ip *); and the panic was at line 256. But if I #undef'd DIAGNOSTICS, then the m_pullup() at line 260 does the right thing and the packet ends up being processed just fine. So I started wondering, (a) why was the test checking for something that apparently wasn't a fatal condition but rather one that is subsequently recovered from a couple of lines later and (b) why panic as a diagnostic "aid" from a recoverable condition rather than just (say) log a message to the console? All of this seems overly severe for no reason that is readily apparent to me. --- cpukit/libnetworking/netinet/ip_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'cpukit/libnetworking') diff --git a/cpukit/libnetworking/netinet/ip_input.c b/cpukit/libnetworking/netinet/ip_input.c index 4cc141933f..238e10cf6b 100644 --- a/cpukit/libnetworking/netinet/ip_input.c +++ b/cpukit/libnetworking/netinet/ip_input.c @@ -251,7 +251,7 @@ ip_input(struct mbuf *m) if (m->m_pkthdr.len < sizeof(struct ip)) goto tooshort; -#ifdef DIAGNOSTIC +#if defined(DIAGNOSTIC) && defined(ORIGINAL_FREEBSD_CODE) if (m->m_len < sizeof(struct ip)) panic("ipintr mbuf too short"); #endif -- cgit v1.2.3