From: Mario Rugiero <mario.rugi...@helpsystems.com>
The current `pcap_set_buffer_size` sets a limit of 2GiB buffer size.
This changeset implements a backwards compatible mechanism to set
bigger buffers.
A new `pcap_set_buffer_size_ex` call is created, taking a `size_t`
instead of an `int`, allowing for buffers as big as the platform
allows.
The `buffer_size` field of `struct pcap_opt` was promoted to `size_t`.
Due to some contexts requiring smaller maximum buffers, a new field
named `max_buffer_size` of type `size_t` was added to the same structure
to account for that, as well as an analogous `min_buffer_size`.
This field is initialized by default to `INT_MAX` to preserve the
behaviour of the older API.
Then, each driver is expected, but not mandated, to fix them to more
suitable values for the platform.
In this RFC, Linux and DPDK are used as examples.
---
pcap-dpdk.c | 2 ++
pcap-int.h | 4 +++-
pcap-linux.c | 1 +
pcap.c | 15 +++++++++++++++
pcap/pcap.h | 5 +++++
5 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/pcap-dpdk.c b/pcap-dpdk.c
index 6c2f21fc..81df91e3 100644
--- a/pcap-dpdk.c
+++ b/pcap-dpdk.c
@@ -964,6 +964,8 @@ pcap_t * pcap_dpdk_create(const char *device, char *ebuf,
int *is_ours)
if (p == NULL)
return NULL;
p->activate_op = pcap_dpdk_activate;
+ p->opt.max_buffer_size = SIZE_MAX;
+
return p;
}
diff --git a/pcap-int.h b/pcap-int.h
index b614efbe..5faa1efb 100644
--- a/pcap-int.h
+++ b/pcap-int.h
@@ -112,7 +112,9 @@ extern "C" {
struct pcap_opt {
char *device;
int timeout; /* timeout for buffering */
- u_int buffer_size;
+ size_t min_buffer_size;/* platform's min buffer size - backends
*should* override it */
+ size_t max_buffer_size;/* platform's max buffer size - backends
*should* override it */
+ size_t buffer_size;
int promisc;
int rfmon; /* monitor mode */
int immediate; /* immediate mode - deliver packets as soon as
they arrive */
diff --git a/pcap-linux.c b/pcap-linux.c
index 31c1a6a0..3b558237 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -517,6 +517,7 @@ pcap_create_interface(const char *device, char *ebuf)
handle->activate_op = pcap_activate_linux;
handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
+ handle->opt.max_buffer_size = SIZE_MAX;
#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
/*
diff --git a/pcap.c b/pcap.c
index ebb992bf..f25fe4a9 100644
--- a/pcap.c
+++ b/pcap.c
@@ -2354,6 +2354,8 @@ pcap_create_common(char *ebuf, size_t size)
/* put in some defaults*/
p->snapshot = 0; /* max packet size unspecified */
p->opt.timeout = 0; /* no timeout specified */
+ p->opt.min_buffer_size = 0;
+ p->opt.max_buffer_size = INT_MAX; /* default to old API's max for
compatibility */
p->opt.buffer_size = 0; /* use the platform's default */
p->opt.promisc = 0;
p->opt.rfmon = 0;
@@ -2494,6 +2496,19 @@ pcap_set_buffer_size(pcap_t *p, int buffer_size)
return (0);
}
+int
+pcap_set_buffer_size_ex(pcap_t *p, size_t buffer_size)
+{
+ if (pcap_check_activated(p))
+ return (PCAP_ERROR_ACTIVATED);
+ if (buffer_size > p->opt.max_buffer_size)
+ return (PCAP_ERROR_BUFFER_TOO_BIG);
+ if (buffer_size < p->opt.min_buffer_size)
+ return (PCAP_ERROR_BUFFER_TOO_SMALL);
+ p->opt.buffer_size = buffer_size;
+ return (0);
+}
+
int
pcap_set_tstamp_precision(pcap_t *p, int tstamp_precision)
{
diff --git a/pcap/pcap.h b/pcap/pcap.h
index 21ea980a..303d58f2 100644
--- a/pcap/pcap.h
+++ b/pcap/pcap.h
@@ -305,6 +305,8 @@ typedef void (*pcap_handler)(u_char *, const struct
pcap_pkthdr *,
#define PCAP_ERROR_CANTSET_TSTAMP_TYPE -10 /* this device doesn't support
setting the time stamp type */
#define PCAP_ERROR_PROMISC_PERM_DENIED -11 /* you don't have permission to
capture in promiscuous mode */
#define PCAP_ERROR_TSTAMP_PRECISION_NOTSUP -12 /* the requested time stamp
precision is not supported */
+#define PCAP_ERROR_BUFFER_TOO_SMALL -13 /* attempted to set a buffer
below the minimum size */
+#define PCAP_ERROR_BUFFER_TOO_BIG -14 /* attempted to set a buffer
below the maximum size */
/*
* Warning codes for the pcap API.
@@ -340,6 +342,9 @@ PCAP_API int pcap_set_timeout(pcap_t *, int);
PCAP_API int pcap_set_tstamp_type(pcap_t *, int);
PCAP_API int pcap_set_immediate_mode(pcap_t *, int);
PCAP_API int pcap_set_buffer_size(pcap_t *, int);
+PCAP_API int pcap_set_buffer_size_ex(pcap_t *, size_t);
+PCAP_API size_t pcap_get_min_buffer_size(pcap_t *);
+PCAP_API size_t pcap_get_max_buffer_size(pcap_t *);
PCAP_API int pcap_set_tstamp_precision(pcap_t *, int);
PCAP_API int pcap_get_tstamp_precision(pcap_t *);
PCAP_API int pcap_activate(pcap_t *);
--
2.20.1
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