diff --git a/pcap.c b/pcap.c index 3d623cf..e95aa6f 100644 --- a/pcap.c +++ b/pcap.c @@ -33,33 +33,12 @@ #include "log.h" #include "pcap.h" #include "iov.h" +#include "tap.h" #define PCAP_VERSION_MINOR 4 static int pcap_fd = -1; -/* See pcap.h from libpcap, or pcap-savefile(5) */ -static const struct { - uint32_t magic; -#define PCAP_MAGIC 0xa1b2c3d4 - - uint16_t major; -#define PCAP_VERSION_MAJOR 2 - - uint16_t minor; -#define PCAP_VERSION_MINOR 4 - - int32_t thiszone; - uint32_t sigfigs; - uint32_t snaplen; - - uint32_t linktype; -#define PCAP_LINKTYPE_ETHERNET 1 -} pcap_hdr = { - PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR, 0, 0, ETH_MAX_MTU, - PCAP_LINKTYPE_ETHERNET -}; - struct pcap_pkthdr { uint32_t tv_sec; uint32_t tv_usec; @@ -162,6 +141,29 @@ void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset) */ void pcap_init(struct ctx *c) { + /* See pcap.h from libpcap, or pcap-savefile(5) */ +#define PCAP_MAGIC 0xa1b2c3d4 +#define PCAP_VERSION_MAJOR 2 +#define PCAP_VERSION_MINOR 4 +#define PCAP_LINKTYPE_ETHERNET 1 + const struct { + uint32_t magic; + uint16_t major; + uint16_t minor; + + int32_t thiszone; + uint32_t sigfigs; + uint32_t snaplen; + + uint32_t linktype; + } pcap_hdr = { + .magic = PCAP_MAGIC, + .major = PCAP_VERSION_MAJOR, + .minor = PCAP_VERSION_MINOR, + .snaplen = tap_l2_max_len(c), + .linktype = PCAP_LINKTYPE_ETHERNET + }; + if (pcap_fd != -1) return; diff --git a/tap.c b/tap.c index ede547c..182a115 100644 --- a/tap.c +++ b/tap.c @@ -82,6 +82,25 @@ static PACKET_POOL_NOINIT(pool_tap6, TAP_MSGS, pkt_buf); #define TAP_SEQS 128 /* Different L4 tuples in one batch */ #define FRAGMENT_MSG_RATE 10 /* # seconds between fragment warnings */ +/** + * tap_l2_max_len() - Maximum frame size (including L2 header) for current mode + * @c: Execution context + */ +unsigned long tap_l2_max_len(const struct ctx *c) +{ + /* NOLINTBEGIN(bugprone-branch-clone): values can be the same */ + switch (c->mode) { + case MODE_PASST: + return L2_MAX_LEN_PASST; + case MODE_PASTA: + return L2_MAX_LEN_PASTA; + case MODE_VU: + return L2_MAX_LEN_VU; + } + /* NOLINTEND(bugprone-branch-clone) */ + ASSERT(0); +} + /** * tap_send_single() - Send a single frame * @c: Execution context diff --git a/tap.h b/tap.h index 84e9fdb..dd39fd8 100644 --- a/tap.h +++ b/tap.h @@ -69,6 +69,7 @@ static inline void tap_hdr_update(struct tap_hdr *thdr, size_t l2len) thdr->vnet_len = htonl(l2len); } +unsigned long tap_l2_max_len(const struct ctx *c); void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto); void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src, struct in_addr dst, size_t l4len, uint8_t proto);