dhcp-message: introduce dhcp_message_{append,get}_option_string()

These are for DHCP options that takes a string e.g. DHCP options
17 (root path), 60 (vendor class identifier), and so on.

diff --git a/src/libsystemd-network/dhcp-message.c b/src/libsystemd-network/dhcp-message.c
index 816d16955d6ba6cbc1d09aa89c346d10b672285f..eafc84c179e1342f5a3b95341df7d3b431083415 100644 (file)
--- a/src/libsystemd-network/dhcp-message.c
+++ b/src/libsystemd-network/dhcp-message.c
@@ -10,6 +10,7 @@
 #include "iovec-wrapper.h"
 #include "ip-util.h"
 #include "network-common.h"
+#include "string-util.h"
 
 static sd_dhcp_message* dhcp_message_free(sd_dhcp_message *message) {
         if (!message)
@@ -186,6 +187,21 @@ int dhcp_message_append_option_addresses(sd_dhcp_message *message, uint8_t code,
         return dhcp_message_append_option(message, code, sizeof(struct in_addr) * n_addr, addr);
 }
 
+int dhcp_message_append_option_string(sd_dhcp_message *message, uint8_t code, const char *data) {
+        assert(message);
+
+        if (isempty(data))
+                return 0;
+
+        if (!string_is_safe(data, STRING_ALLOW_BACKSLASHES | STRING_ALLOW_QUOTES | STRING_ALLOW_GLOBS))
+                return -EINVAL;
+
+        if (dhcp_message_has_option(message, code))
+                return -EEXIST;
+
+        return dhcp_message_append_option(message, code, strlen(data), data);
+}
+
 int dhcp_message_get_option(sd_dhcp_message *message, uint8_t code, size_t length, void *ret) {
         int r;
 
@@ -281,6 +297,38 @@ int dhcp_message_get_option_addresses(sd_dhcp_message *message, uint8_t code, si
         return 0;
 }
 
+int dhcp_message_get_option_string(sd_dhcp_message *message, uint8_t code, char **ret) {
+        int r;
+
+        assert(message);
+
+        _cleanup_(iovec_done) struct iovec iov = {};
+        r = dhcp_message_get_option_alloc(message, code, &iov);
+        if (r < 0)
+                return r;
+
+        if (!iovec_is_set(&iov))
+                return -ENODATA;
+
+        /* Allow NUL at the end for buggy DHCP servers, but refuse intermediate NUL. */
+        if (memchr(iov.iov_base, 0, iov.iov_len - 1))
+                return -EBADMSG;
+
+        /* Note, dhcp_message_get_option_alloc() -> tlv_get_alloc() allocates an extra byte to make
+         * iov.iov_base can be handled as a NUL-terminated string. Hence, we can directly pass it to
+         * isempty() and string_is_safe(). */
+
+        if (isempty(iov.iov_base))
+                return -ENODATA;
+
+        if (!string_is_safe(iov.iov_base, STRING_ALLOW_BACKSLASHES | STRING_ALLOW_QUOTES | STRING_ALLOW_GLOBS))
+                return -EBADMSG;
+
+        if (ret)
+                *ret = TAKE_PTR(iov.iov_base);
+        return 0;
+}
+
 static int dhcp_message_verify_header(
                 const struct iovec *iov,
                 uint8_t op,

diff --git a/src/libsystemd-network/dhcp-message.h b/src/libsystemd-network/dhcp-message.h
index 6d4e1939b0f2c129565d9568e83fdad86554c5ce..d47d7ba4094ba49214a3ae430f6147e8f063eee7 100644 (file)
--- a/src/libsystemd-network/dhcp-message.h
+++ b/src/libsystemd-network/dhcp-message.h
@@ -37,6 +37,7 @@ int dhcp_message_append_option_be32(sd_dhcp_message *message, uint8_t code, be32
 int dhcp_message_append_option_sec(sd_dhcp_message *message, uint8_t code, usec_t usec);
 int dhcp_message_append_option_address(sd_dhcp_message *message, uint8_t code, const struct in_addr *addr);
 int dhcp_message_append_option_addresses(sd_dhcp_message *message, uint8_t code, size_t n_addr, const struct in_addr *addr);
+int dhcp_message_append_option_string(sd_dhcp_message *message, uint8_t code, const char *data);
 
 int dhcp_message_get_option(sd_dhcp_message *message, uint8_t code, size_t length, void *ret);
 int dhcp_message_get_option_alloc(sd_dhcp_message *message, uint8_t code, struct iovec *ret);
@@ -47,6 +48,7 @@ int dhcp_message_get_option_be32(sd_dhcp_message *message, uint8_t code, be32_t
 int dhcp_message_get_option_sec(sd_dhcp_message *message, uint8_t code, bool max_as_infinity, usec_t *ret);
 int dhcp_message_get_option_address(sd_dhcp_message *message, uint8_t code, struct in_addr *ret);
 int dhcp_message_get_option_addresses(sd_dhcp_message *message, uint8_t code, size_t *ret_n_addr, struct in_addr **ret_addr);
+int dhcp_message_get_option_string(sd_dhcp_message *message, uint8_t code, char **ret);
 
 int dhcp_message_parse(
                 const struct iovec *iov,

diff --git a/src/libsystemd-network/test-dhcp-message.c b/src/libsystemd-network/test-dhcp-message.c
index 7c1c255f951f670c721efae47140e15fa6f8f151..31e0754d9316dc2c683ad1a55f16848ae2948110 100644 (file)
--- a/src/libsystemd-network/test-dhcp-message.c
+++ b/src/libsystemd-network/test-dhcp-message.c
@@ -2,12 +2,14 @@
 
 #include <net/if_arp.h>
 
+#include "alloc-util.h"
 #include "dhcp-message.h"
 #include "dhcp-protocol.h"
 #include "ether-addr-util.h"
 #include "iovec-util.h"
 #include "iovec-wrapper.h"
 #include "random-util.h"
+#include "strv.h"
 #include "tests.h"
 
 static void verify_header(sd_dhcp_message *m, uint32_t xid, const struct hw_addr_data *hw_addr) {
@@ -79,6 +81,19 @@ static void verify_addresses(
         ASSERT_EQ(memcmp(addrs, ntp, sizeof(struct in_addr) * n), 0);
 }
 
+static void verify_string(sd_dhcp_message *m, const char *expected) {
+        _cleanup_free_ char *s = NULL;
+        ASSERT_OK(dhcp_message_get_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, &s));
+        ASSERT_STREQ(s, expected);
+}
+
+static void verify_multiple_strings(sd_dhcp_message *m, char * const *expected) {
+        _cleanup_free_ char *s = NULL;
+        ASSERT_OK(dhcp_message_get_option_string(m, SD_DHCP_OPTION_ROOT_PATH, &s));
+        _cleanup_free_ char *joined = ASSERT_NOT_NULL(strv_join(expected, /* separator= */ ""));
+        ASSERT_STREQ(s, joined);
+}
+
 TEST(dhcp_message) {
         _cleanup_(sd_dhcp_message_unrefp) sd_dhcp_message *m = NULL;
 
@@ -105,6 +120,9 @@ TEST(dhcp_message) {
                 { .s_addr = htobe32(0xC0000204) },
         };
 
+        const char *vendor_class = "hogehoge";
+        char **root_path = STRV_MAKE("/path/to/root", "/hogehoge/foofoo");
+
         ASSERT_OK(dhcp_message_init_header(
                                   m,
                                   BOOTREQUEST,
@@ -118,6 +136,11 @@ TEST(dhcp_message) {
         ASSERT_ERROR(dhcp_message_append_option(m, SD_DHCP_OPTION_PAD, 0, NULL), EINVAL);
         ASSERT_ERROR(dhcp_message_append_option(m, SD_DHCP_OPTION_END, 0, NULL), EINVAL);
 
+        /* multiple strings */
+        STRV_FOREACH(s, root_path)
+                ASSERT_OK(dhcp_message_append_option(m, SD_DHCP_OPTION_ROOT_PATH, strlen(*s), *s));
+        verify_multiple_strings(m, root_path);
+
         /* flag */
         ASSERT_ERROR(dhcp_message_get_option_flag(m, SD_DHCP_OPTION_RAPID_COMMIT), ENODATA);
         ASSERT_OK(dhcp_message_append_option_flag(m, SD_DHCP_OPTION_RAPID_COMMIT));
@@ -154,6 +177,19 @@ TEST(dhcp_message) {
         ASSERT_OK(dhcp_message_append_option_addresses(m, SD_DHCP_OPTION_NTP_SERVER, ELEMENTSOF(ntp) - 1, ntp + 1));
         verify_addresses(m, ELEMENTSOF(ntp), ntp);
 
+        /* string */
+        ASSERT_ERROR(dhcp_message_get_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, NULL), ENODATA);
+        ASSERT_OK(dhcp_message_append_option(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, 0, NULL));
+        ASSERT_ERROR(dhcp_message_get_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, NULL), ENODATA);
+        ASSERT_OK(dhcp_message_append_option(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, 1, "\0"));
+        ASSERT_ERROR(dhcp_message_get_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, NULL), ENODATA);
+        ASSERT_OK(dhcp_message_append_option(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, 9, "hoge\0hoge"));
+        ASSERT_ERROR(dhcp_message_get_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, NULL), EBADMSG);
+        ASSERT_ERROR(dhcp_message_append_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, vendor_class), EEXIST);
+        dhcp_message_remove_option(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER);
+        ASSERT_OK(dhcp_message_append_option_string(m, SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, vendor_class));
+        verify_string(m, vendor_class);
+
         /* build and parse */
         _cleanup_(iovw_done_free) struct iovec_wrapper iovw = {};
         ASSERT_OK(dhcp_message_build(m, &iovw));
@@ -174,12 +210,14 @@ TEST(dhcp_message) {
 
         /* verify parsed message */
         verify_header(m2, xid, &hw_addr);
+        verify_multiple_strings(m2, root_path);
         verify_flag(m2);
         verify_u8(m2, DHCP_DISCOVER);
         verify_u16(m2, 512);
         verify_sec(m2, lease_time);
         verify_address(m2, &addr);
         verify_addresses(m2, ELEMENTSOF(ntp), ntp);
+        verify_string(m2, vendor_class);
 
         /* build again, and verify the packet */
         _cleanup_(iovw_done_free) struct iovec_wrapper iovw2 = {};