site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com The assertion occurred because you replaced the contents of pkthdr (which is private) with something else that doesn't belong with that mbuf; don't use mbuf_pkthdr_setheader(). I'm not quite clear on what you're trying to do, but instead, if you want to prepend data, use mbuf_prepend(). If you want to associate private data to the mbuf, use mbuf_tag_*. If you really want to change the linkage of mbufs, use mbuf_setnext(). For the latter, you'd have to copy over the contents of the head mbuf to another mbuf, set the mbuf length to 0, and point the next pointer to your mbuf which then points to the mbuf containing the original data. Adi On Dec 17, 2009, at 9:15 AM, Dmitriy Arekhta wrote:
Hi List,
I'm working with interface filter and I should add to the output network packets custom header. In my ctl_send routine I have pointer to the source mbuf, so I do the following to chain custom mbuf to front:
UInt32 srcMbufDataLen = mbuf_chain_size(m); // len of current buffer
UInt32 dstMbufDataLen = srcMbufDataLen; mbuf_t dstMbuf = NULL; // mbuf that will be passed to dlil mbuf_t mbufToSend = m; unsigned int dstMbufChunks = 1;
UInt32 srcMbufOffset = 0; errno_t result = KERN_SUCCESS;
KTHPAdapter *adapter = static_cast<KTHPAdapter *>(userdata);
if (adapter->fFilter.IsThpModeEnabled) { dstMbufDataLen += sizeof(KTHPPacketHeader);
// Let's try to allocate new mbuf result = mbuf_allocpacket(MBUF_DONTWAIT, // blocking or non-blocking sizeof(KTHPPacketHeader), // entire packet len &dstMbufChunks, // total packet chunks &dstMbuf );
if (result != KERN_SUCCESS || !dstMbuf || !mbuf_data(dstMbuf)) { ALERT(dstMbufDataLen, result, "Couldn't allocate packet to send, dstMbufDataLen, result"); mbuf_freem(m);
return result; }
mbuf_setlen(dstMbuf, sizeof(KTHPPacketHeader));
mbufToSend = dstMbuf;
mbuf_setnext(mbufToSend, m);
// Update an old packets for(mbuf_t c = m; c != NULL; c = mbuf_next(c)) { mbuf_pkthdr_setheader(c, mbuf_data(mbufToSend)); } mbuf_pkthdr_setlen(m, dstMbufDataLen);
// Update the new packet mbuf_setflags(mbufToSend, mbuf_flags(m)); mbuf_settype(mbufToSend, mbuf_type(m));
mbuf_pkthdr_setheader(mbufToSend, 0); mbuf_pkthdr_setlen(mbufToSend, dstMbufDataLen);
// Clear status fiels of the old mbuf mbuf_setflags(m, 0);
}
When I try to send this packet to the network interface I got the kernel panic in m_freem_list(struct mbuf *m)
panic(cpu 0 caller 0x0038DA21): assertion failed: m->m_ext.ext_free == m_16kfree, file: /SourceCache/xnu/xnu-1228.15.4/bsd/kern/uipc_mbuf.c, line: 3639
What do I do wrong? Any advice? Thanks :)
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