mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-14 10:09:48 +00:00
Code Issues Releases Activity

Fix bug where an mbuf was being written to without checking M_WRITABLE().

Browse Source 
Eliminate some of the unnecessary complexity of ng_ether_glueback_header().
Simplify two functions a bit by doing the NG_FREE_META(meta) earlier.

Reviewed by:	julian, brian
MFC after:	1 week
This commit is contained in:
Archie Cobbs 2002-06-05 23:32:56 +00:00
parent d3479b8238
commit 7b9f235f4c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=97896
1 changed files with 24 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
sys/netgraph/ng_ether.c
View File

@ -358,15 +358,12 @@ static int
ng_ether_glueback_header(struct mbuf **mp, struct ether_header *eh)
{
struct mbuf *m = *mp;
uintfptr_t room;
int error = 0;
/*
* Possibly the header is already on the front.
* If this is the case so just move the markers back
* to re-include it. We lucked out.
* This allows us to avoid a yucky m_pullup
* in later nodes if it works.
* Optimize for the case where the header is already in place
* at the front of the mbuf. This is actually quite likely
* because many Ethernet drivers generate packets this way.
*/
if (eh == mtod(m, struct ether_header *) - 1) {
m->m_len += sizeof(*eh);
@ -375,52 +372,18 @@ ng_ether_glueback_header(struct mbuf **mp, struct ether_header *eh)
goto done;
}
/*
* Alternatively there may be room even though
* it is stored somewhere else. If so, copy it in.
* This only safe because we KNOW that this packet has
* just been generated by an ethernet card, so there are
* no aliases to the buffer (not so for outgoing packets).
* Nearly all ethernet cards will end up producing mbufs
* that fall into these cases. So we are not optimizing
* contorted cases.
*/
if ((m->m_flags & M_EXT) != 0) {
room = mtod(m, caddr_t) - m->m_ext.ext_buf;
if (room > m->m_ext.ext_size) /* garbage, fail immediately */
room = 0;
} else
room = mtod(m, caddr_t) - m->m_pktdat;
/*
* If we have room, just copy it and adjust
*/
if (room >= sizeof(*eh)) {
m->m_len += sizeof(*eh);
m->m_data -= sizeof(*eh);
m->m_pkthdr.len += sizeof(*eh);
goto copy;
}
/*
* Doing anything more is likely to get more
* expensive than it's worth..
* it's probable that everything else is in one
* big lump. The next node will do an m_pullup()
* for exactly the amount of data it needs and
* hopefully everything after that will not
* need one. So let's just use M_PREPEND.
*/
M_PREPEND(m, sizeof (*eh), M_DONTWAIT);
/* Prepend the header back onto the front of the mbuf */
M_PREPEND(m, sizeof(*eh), M_DONTWAIT);
if (m == NULL) {
error = ENOBUFS;
goto done;
}
copy:
/* Copy header and return (possibly new) mbuf */
bcopy((caddr_t)eh, mtod(m, struct ether_header *), sizeof(*eh));
/* Copy header into front of mbuf */
bcopy(eh, mtod(m, void *), sizeof(*eh));
done:
/* Done */
*mp = m;
return error;
}
@ -629,34 +592,39 @@ ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta)
const priv_p priv = NG_NODE_PRIVATE(node);
struct ifnet *const ifp = priv->ifp;
/* Discard meta info */
NG_FREE_META(meta);
/* Check whether interface is ready for packets */
if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
NG_FREE_M(m);
NG_FREE_META(meta);
return (ENETDOWN);
}
/* Make sure header is fully pulled up */
if (m->m_pkthdr.len < sizeof(struct ether_header)) {
NG_FREE_M(m);
NG_FREE_META(meta);
return (EINVAL);
}
if (m->m_len < sizeof(struct ether_header)
&& (m = m_pullup(m, sizeof(struct ether_header))) == NULL) {
NG_FREE_META(meta);
&& (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
return (ENOBUFS);
}
/* Drop in the MAC address if desired */
if (priv->autoSrcAddr) {
/* Make the mbuf writable if it's not already */
if (!M_WRITABLE(m)
&& (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
return (ENOBUFS);
/* Overwrite source MAC address */
bcopy((IFP2AC(ifp))->ac_enaddr,
mtod(m, struct ether_header *)->ether_shost,
ETHER_ADDR_LEN);
}
/* Send it on its way */
NG_FREE_META(meta);
return ether_output_frame(ifp, m);
}
@ -669,16 +637,16 @@ ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta)
const priv_p priv = NG_NODE_PRIVATE(node);
struct ether_header *eh;
/* Discard meta info */
NG_FREE_META(meta);
/* Check length and pull off header */
if (m->m_pkthdr.len < sizeof(*eh)) {
NG_FREE_M(m);
NG_FREE_META(meta);
return (EINVAL);
}
if (m->m_len < sizeof(*eh) && (m = m_pullup(m, sizeof(*eh))) == NULL) {
NG_FREE_META(meta);
if (m->m_len < sizeof(*eh) && (m = m_pullup(m, sizeof(*eh))) == NULL)
return (ENOBUFS);
}
eh = mtod(m, struct ether_header *);
m->m_data += sizeof(*eh);
m->m_len -= sizeof(*eh);
@ -686,7 +654,6 @@ ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta)
m->m_pkthdr.rcvif = priv->ifp;
/* Route packet back in */
NG_FREE_META(meta);
ether_demux(priv->ifp, eh, m);
return (0);
}