Petri Savolainen(psavol) replied on github web page: include/odp/api/spec/packet.h line 28 @@ -401,30 +401,39 @@ uint32_t odp_packet_buf_len(odp_packet_t pkt); /** * Packet data pointer * - * Returns the current packet data pointer. When a packet is received - * from packet input, this points to the first byte of the received - * packet. Packet level offsets are calculated relative to this position. + * Returns pointer to the first byte of packet data. When packet is segmented, + * only a portion of packet data follows the pointer. When unsure, use e.g. + * odp_packet_seg_len() to check the data length following the pointer. Packet + * level offsets are calculated relative to this position. * - * User can adjust the data pointer with head_push/head_pull (does not modify - * segmentation) and add_data/rem_data calls (may modify segmentation). + * When a packet is received from packet input, this points to the first byte + * of the received packet. Pool configuration parameters may be used to ensure + * that the first packet segment contains all/most of the data relevant to the + * application. + * + * User can adjust the data pointer with e.g. push_head/pull_head (does not + * modify segmentation) and extend_head/trunc_head (may modify segmentation) + * calls. * * @param pkt Packet handle * * @return Pointer to the packet data * - * @see odp_packet_l2_ptr(), odp_packet_seg_len() + * @see odp_packet_seg_len(), odp_packet_push_head(), odp_packet_extend_head()
Comment: seg_len / push_head / extend_head are mentioned above. Packet_offset is not specialized for handling first N bytes of packet, so it's not directly related to these ones. > Petri Savolainen(psavol) wrote: > packet_offset is for different purpose (access data on arbitrary offset), > these calls are optimized for the common case (offset zero). Also > odp_packet_seg_data_len(), the new data_seg_len(), odp_packet_l2_ptr(), > odp_packet_l3_ptr() and odp_packet_l4_ptr() output seg len, but we don't > need to list all possible ways to get it. It's enough that the reader > understands that a packet may have segments and segment length is different > thing than total packet length >> Dmitry Eremin-Solenikov(lumag) wrote: >> And here too, please. >>> Dmitry Eremin-Solenikov(lumag) wrote: >>> odp_packet_seg_len() **or odp_packet_offset()**, if you don't mind. https://github.com/Linaro/odp/pull/497#discussion_r170183024 updated_at 2018-02-23 07:36:58
