os_mbuf_extend

void *os_mbuf_extend(struct os_mbuf *om, uint16_t len);

Increases the length of an mbuf chain by the specified amount. If there is not sufficient room in the last buffer, a new buffer is allocated and appended to the chain. It is an error to request more data than can fit in a single buffer.

Arguments

Arguments	Description
om	Pointer to mbuf chain
len	Number of bytes to increase packet header

Returned values

Pointer to start of extended data. Caller is guaranteed that there are at least len bytes from this pointer to the end of the mbuf.

Returns NULL if extension fails due to insufficient mbufs or len too large.

Example

    uint8_t *dptr;
	struct os_mbuf *om;
    struct my_data_struct my_data;	
	
    /* Obtain enough room to add "my_data" to an mbuf chain */
    dptr = os_mbuf_extend(om, sizeof(struct my_data_struct));
    if (dptr) {
        memcpy(dptr, &my_data, sizeof(struct my_data_struct));
    }