From: Tiago Lam <tiago....@intel.com> In its current implementation dp_packet_shift() is also unaware of multi-seg mbufs (that holds data in memory non-contiguously) and assumes that data exists contiguously in memory, memmove'ing data to perform the shift.
To add support for multi-seg mbufs a new set of functions was introduced, dp_packet_mbuf_shift() and dp_packet_mbuf_write(). These functions are used by dp_packet_shift(), when handling multi-seg mbufs, to shift and write data within a chain of mbufs. Signed-off-by: Tiago Lam <tiago....@intel.com> Acked-by: Eelco Chaudron <echau...@redhat.com> Signed-off-by: Michal Obrembski <michalx.obremb...@intel.com> --- lib/dp-packet.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/dp-packet.h | 3 ++ 2 files changed, 108 insertions(+) diff --git a/lib/dp-packet.c b/lib/dp-packet.c index 582e24d..c7675fd 100644 --- a/lib/dp-packet.c +++ b/lib/dp-packet.c @@ -24,6 +24,11 @@ #include "openvswitch/dynamic-string.h" #include "util.h" +#ifdef DPDK_NETDEV +#define MBUF_BUF_END(BUF_ADDR, BUF_LEN) \ + (char *) (((char *) BUF_ADDR) + BUF_LEN) +#endif + static void dp_packet_init__(struct dp_packet *b, size_t allocated, enum dp_packet_source source) { @@ -311,6 +316,100 @@ dp_packet_prealloc_headroom(struct dp_packet *b, size_t size) } } +#ifdef DPDK_NETDEV +/* Write len data bytes in a mbuf at specified offset. + * + * 'mbuf', pointer to the destination mbuf where 'ofs' is, and the mbuf where + * the data will first be written. + * 'ofs', the offset within the provided 'mbuf' where 'data' is to be written. + * 'len', the size of the to be written 'data'. + * 'data', pointer to the to be written bytes. + * + * Note: This function is the counterpart of the `rte_pktmbuf_read()` function + * available with DPDK, in the rte_mbuf.h */ +void +dp_packet_mbuf_write(struct rte_mbuf *mbuf, int16_t ofs, uint32_t len, + const void *data) +{ + char *dst_addr; + uint16_t data_len; + int len_copy; + while (mbuf) { + if (len == 0) { + break; + } + + dst_addr = rte_pktmbuf_mtod_offset(mbuf, char *, ofs); + data_len = MBUF_BUF_END(mbuf->buf_addr, mbuf->buf_len) - dst_addr; + + len_copy = MIN(len, data_len); + /* We don't know if 'data' is the result of a rte_pktmbuf_read() call, + * in which case we may end up writing to the same region of memory we + * are reading from and overlapping. Hence the use of memmove() here */ + memmove(dst_addr, data, len_copy); + + data = ((char *) data) + len_copy; + len -= len_copy; + ofs = 0; + + mbuf->data_len = len_copy; + mbuf = mbuf->next; + } +} + +static void +dp_packet_mbuf_shift_(struct rte_mbuf *dbuf, int16_t dst_ofs, + const struct rte_mbuf *sbuf, uint16_t src_ofs, int len) +{ + char *rd = xmalloc(sizeof(*rd) * len); + const char *wd = rte_pktmbuf_read(sbuf, src_ofs, len, rd); + + ovs_assert(wd); + + dp_packet_mbuf_write(dbuf, dst_ofs, len, wd); + + free(rd); +} + +/* Similarly to dp_packet_shift(), shifts the data within the mbufs of a + * dp_packet of DPBUF_DPDK source by 'delta' bytes. + * Caller must make sure of the following conditions: + * - When shifting left, delta can't be bigger than the data_len available in + * the last mbuf; + * - When shifting right, delta can't be bigger than the space available in the + * first mbuf (buf_len - data_off). + * Both these conditions guarantee that a shift operation doesn't fall outside + * the bounds of the existing mbufs, so that the first and last mbufs (when + * using multi-segment mbufs), remain the same. */ +static void +dp_packet_mbuf_shift(struct dp_packet *b, int delta) +{ + uint16_t src_ofs; + int16_t dst_ofs; + + struct rte_mbuf *mbuf = CONST_CAST(struct rte_mbuf *, &b->mbuf); + struct rte_mbuf *tmbuf = rte_pktmbuf_lastseg(mbuf); + + if (delta < 0) { + ovs_assert(-delta <= tmbuf->data_len); + } else { + ovs_assert(delta < (mbuf->buf_len - mbuf->data_off)); + } + + /* Set the destination and source offsets to copy to */ + dst_ofs = delta; + src_ofs = 0; + + /* Shift data from src mbuf and offset to dst mbuf and offset */ + dp_packet_mbuf_shift_(mbuf, dst_ofs, mbuf, src_ofs, + rte_pktmbuf_pkt_len(mbuf)); + + /* Update mbufs' properties, and if using multi-segment mbufs, first and + * last mbuf's data_len also needs to be adjusted */ + mbuf->data_off = mbuf->data_off + dst_ofs; +} +#endif + /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes. * For example, a 'delta' of 1 would cause each byte of data to move one byte * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each @@ -323,6 +422,12 @@ dp_packet_shift(struct dp_packet *b, int delta) : true); if (delta != 0) { +#ifdef DPDK_NETDEV + if (b->source == DPBUF_DPDK) { + dp_packet_mbuf_shift(b, delta); + return; + } +#endif char *dst = (char *) dp_packet_data(b) + delta; memmove(dst, dp_packet_data(b), dp_packet_size(b)); dp_packet_set_data(b, dst); diff --git a/lib/dp-packet.h b/lib/dp-packet.h index 321eeb6..7b2c4a0 100644 --- a/lib/dp-packet.h +++ b/lib/dp-packet.h @@ -156,6 +156,9 @@ static inline void *dp_packet_at_assert(const struct dp_packet *, #ifdef DPDK_NETDEV static inline const struct rte_mbuf * dp_packet_mbuf_from_offset(const struct dp_packet *b, size_t *offset); +void +dp_packet_mbuf_write(struct rte_mbuf *mbuf, int16_t ofs, uint32_t len, + const void *data); #endif static inline void *dp_packet_tail(const struct dp_packet *); static inline void *dp_packet_end(const struct dp_packet *); -- 2.7.4 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev