os_mbuf_adj

void os_mbuf_adj(struct os_mbuf *mp, int req_len);

Trims req_len bytes from either the head (if positive) or tail (if negative) of an mbuf chain. Adjusts the packet length of the mbuf chain if mp points to a packet header mbuf. When trimming from the head, no mbufs are freed. When trimming from the tail, any mbufs of zero length left at the end of the chain are freed.

Arguments

Arguments	Description
mp	Pointer to mbuf. Can be head of a chain of mbufs, a single mbuf or a packet header mbuf
req_len	Number of bytes to trim from head or tail of mbuf

Returned values

None

Notes

Example

    uint16_t pktlen;
	struct os_mbuf *om;
	struct my_pkt_header hdr;
	
	/* Get mbuf chain length */
	pktlen = OS_MBUF_PKTLEN(om);
	
	/* Strip header from mbuf chain */
    os_mbuf_adj(om, sizeof(struct my_pkt_header));
    pktlen -= sizeof(struct my_pkt_header);

    /* New packet length should be old packet length minus stripped header */
	assert(pktlen == OS_MBUF_PKTLEN(om));