bsd/kern/uipc_mbuf2.c

120  * ensure that [off, off + len) is contiguous on the mbuf chain "m".
121  * packet chain before "off" is kept untouched.
130 m_pulldown(struct mbuf *m, int off, int len, int *offp)
155 	if (off + len > MHLEN)
163 		if (dlen >= off + len)
169 			if (mlen >= off + len)
177 		prevlen = off + len;
183 	if (off + len > MCLBYTES)
190 		prevlen = off + len;
193 		if (dlen >= off + len)
198 			prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;
200 			if (mlen >= off + len)
205 				prevmlen = (off + len > MHLEN) ? MCLBYTES
224 	while (n != NULL && off > 0) {
225 		if (n->m_len > off)
227 		off -= n->m_len;
239 	 * the target data is on <n, off>.
242 	if ((off == 0 || offp) && len <= n->m_len - off)
250 	 * when len < n->m_len - off and off != 0, it is a special case.
251 	 * len bytes from <n, off> sits in single mbuf, but the caller does
252 	 * not like the starting position (off).
253 	 * chop the current mbuf into two pieces, set off to 0.
255 	if (len < n->m_len - off) {
256 		o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
261 		n->m_len = off;
265 		off = 0;
270 	 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
274 	hlen = n->m_len - off;
303 	if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
310 	if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
314 		bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
317 		off = 0;
341 	/* get hlen from <n, off> into <o, 0> */
343 	bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
352 	off = 0;
361 	printf(" (off=%d)\n", off);
365 		*offp = off;
614 	 * XXXMAC: we should probably pass off the initialization, and