Re: [PATCH v10 3/5] net: add a helper for making RARP packet
From: Olivier Matz <hidden>
Date: 2018-01-16 09:01:29
Hi Xiao, Please find few comments below. On Wed, Jan 10, 2018 at 09:23:54AM +0800, Xiao Wang wrote:
quoted hunk ↗ jump to hunk
Suggested-by: Maxime Coquelin <redacted> Signed-off-by: Xiao Wang <redacted> Reviewed-by: Maxime Coquelin <redacted> --- lib/librte_net/Makefile | 1 + lib/librte_net/rte_arp.c | 42 ++++++++++++++++++++++++++++++++++++++ lib/librte_net/rte_arp.h | 17 +++++++++++++++ lib/librte_net/rte_net_version.map | 6 ++++++ 4 files changed, 66 insertions(+) create mode 100644 lib/librte_net/rte_arp.cdiff --git a/lib/librte_net/Makefile b/lib/librte_net/Makefile index 5e8a76b68..ab290c382 100644 --- a/lib/librte_net/Makefile +++ b/lib/librte_net/Makefile@@ -13,6 +13,7 @@ LIBABIVER := 1 SRCS-$(CONFIG_RTE_LIBRTE_NET) := rte_net.c SRCS-$(CONFIG_RTE_LIBRTE_NET) += rte_net_crc.c +SRCS-$(CONFIG_RTE_LIBRTE_NET) += rte_arp.c # install includes SYMLINK-$(CONFIG_RTE_LIBRTE_NET)-include := rte_ip.h rte_tcp.h rte_udp.h rte_esp.hdiff --git a/lib/librte_net/rte_arp.c b/lib/librte_net/rte_arp.c new file mode 100644 index 000000000..d7223b044 --- /dev/null +++ b/lib/librte_net/rte_arp.c@@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2018 Intel Corporation + */ + +#include <arpa/inet.h> + +#include <rte_arp.h> + +#define RARP_PKT_SIZE 64 +int +rte_net_make_rarp_packet(struct rte_mbuf *mbuf, const struct ether_addr *mac) +{ + struct ether_hdr *eth_hdr; + struct arp_hdr *rarp; + + if (mbuf->buf_len < RARP_PKT_SIZE) + return -1; + + /* Ethernet header. */ + eth_hdr = rte_pktmbuf_mtod(mbuf, struct ether_hdr *); + memset(eth_hdr->d_addr.addr_bytes, 0xff, ETHER_ADDR_LEN); + ether_addr_copy(mac, ð_hdr->s_addr); + eth_hdr->ether_type = htons(ETHER_TYPE_RARP); + + /* RARP header. */ + rarp = (struct arp_hdr *)(eth_hdr + 1); + rarp->arp_hrd = htons(ARP_HRD_ETHER); + rarp->arp_pro = htons(ETHER_TYPE_IPv4); + rarp->arp_hln = ETHER_ADDR_LEN; + rarp->arp_pln = 4; + rarp->arp_op = htons(ARP_OP_REVREQUEST); + + ether_addr_copy(mac, &rarp->arp_data.arp_sha); + ether_addr_copy(mac, &rarp->arp_data.arp_tha); + memset(&rarp->arp_data.arp_sip, 0x00, 4); + memset(&rarp->arp_data.arp_tip, 0x00, 4); + + mbuf->data_len = RARP_PKT_SIZE; + mbuf->pkt_len = RARP_PKT_SIZE; + + return 0; +}
You don't check that there is enough tailroom to write the packet data.
Also, nothing verifies that the mbuf passed to the function is empty.
I suggest to do the allocation in this function, what do you think?
You can also use rte_pktmbuf_append() to check for the tailroom and
update data_len/pkt_len:
m = rte_pktmbuf_alloc();
if (m == NULL)
return NULL;
eth_hdr = rte_pktmbuf_append(m, RARP_PKT_SIZE);
if (eth_hdr == NULL) {
m_freem(m);
return NULL;
}
eth_hdr->... = ...;
...
rarp = (struct arp_hdr *)(eth_hdr + 1);
rarp->... = ...;
...
return m;